Majeti Fetrie, thighs bulging like totara trunks, became a national hero this week. Pumping a total 309kg in his weightlifting class, Fetrie won Ghana's first gold medal at the Commonwealth Games.

After the glamour and adulation in Melbourne, Fetrie will return to the real world when he flies back to his wife in Ghana's capital of Accra. The west African nation is among the world's poorest, with a population five times the size of New Zealand's sharing an economy roughly 50 times smaller.

The north of Fetrie's homeland is regularly and brutally scorched by drought, the land is overgrazed and has been stripped of forest. Wildlife is being devastated by poaching and the loss of habitat, and pollution means there is not enough clean water for Ghana's 21 million people.

A third of the population lives below the poverty line, their life expectancy shortened to about 58 years by endemic hepatitis, typhoid and diarrhoea, and the modern plague of HIV/Aids: 350,000 adults live with a disease that killed 30,000 in 2003.

This is the reality that lay behind the parade of athletes at last Wednesday's opening ceremony - a Commonwealth and a sporting tournament dominated by the economies of a handful of wealthy nations and a medal tally that underlines disparity and disadvantage.

The richest nations of Britain, Canada, Australia, New Zealand and Singapore, with a total population of 121.6 million and a combined gross domestic product of more than US$3.5 trillion, fielded more than 1700 athletes, about 43 per cent of competitors. The developing Commonwealth, with about 1.8 billion people and a combined economy of US$4.8 trillion (dominated by the vast Indian GDP of US$3.6 trillion) sent 2200 athletes to Melbourne.

At the 2002 Manchester Games, the rich nations, mainly Australia and the United Kingdom, won two-thirds of all medals and a similar share of gold. The medal table from these Games will look much the same. At the start of the week Australia, the UK, Canada, New Zealand and Singapore had won 251 medals, 80 of them gold. The rest of the Commonwealth had gathered 81 medals, with 32 golds.

Nobody pretends it can be otherwise. The Commonwealth embraces almost a third of the world's population, from the 11,000 inhabitants of tiny Tuvalu to India's 1 billion, most of them living in the poorest parts of the globe.

The Commonwealth does not hide its problems. South Africa could not compete in the Games for almost 40 years because of apartheid. Nigeria was suspended from the organisation for two years. Zimbabwe has withdrawn because of Commonwealth action against the excesses of Robert Mugabe's regime.

The latest issue of the Commonwealth Press Union's new magazine, CPQ, reports on repression, sometimes brutal, of media freedom in Uganda, Tanzania, Sierra Leone, the Maldives, Zambia and The Gambia, where journalists have been forced into exile, presses destroyed and outspoken editor Deyda Hydara shot dead in a still unsolved murder.

Only a tiny tip of this has broken through the surface at Melbourne, reflected in the appointment of the charity Plan to boost awareness of issues facing the developing Commonwealth, and especially those confronting children. Games organisers want to use sports to help raise funds for community development projects and to encourage Australians to either sponsor a child or support a project in the Commonwealth.

Commonwealth Secretary-General Don McKinnon's Games message pushed the concept of sports as a means of changing lives: "Sport empowers people, particularly young people. It provides them with role models. It gives them the confidence that they can change their own lives and make a difference in the lives of others."

And there has been movement. Few women were able to compete in the early Games. In Melbourne males still dominate - 62 per cent of athletes are men - but there have been significant, if still slow, advances for females.

Throughout Asia, the Americas, the Caribbean, Africa and the Pacific, two-thirds or more of the national teams are men. Brunei, Falkland Islands, St Helena, Dominica, Montserrat, Turks and Caicos, The Gambia and Tuvalu have no women competitors.

But the proportion of male team members falls to about 58 per cent for Canada and the UK, 52 per cent for Australia and New Zealand, and to equal numbers for Malta and St Kitts and Nevis. The teams from Singapore, Jamaica, St Vincent and the Grenadines, Malawi, Mozambique and Nigeria have more women than men.

Yet last week's parade of athletes underlined the vast loss of human potential to poverty. New Zealand's 246-member squad was larger than those of massive India, Pakistan and Bangladesh, and two to 18 times bigger than all African teams except South Africa.

The reason lies in the numbers. New Zealand's GDP, in US dollar purchasing power parity terms, is larger than that of every African Commonwealth nation except Nigeria and South Africa, and our per-capita GDP of US$24,100 outstrips all Commonwealth countries except the UK, Canada, Australia, Singapore, the offshore tax havens of Bermuda and the Cayman and British Virgin islands, Gibraltar and the Falkland Islands, whose tiny economy has rocketed since the 1983 war through military bases, the sale of fishing licences and potential oil reserves of 500,000 barrels a day.

Across the Commonwealth, the disparities are enormous. Per-capita GDP of US$32,800 in Canada, US$32,000 in Australia, US$30,900 in the UK and US$29,700 in Singapore compare with average figures of US$9975 in Asian member states, US$11,971 in the Caribbean, US$4116 in Africa and an appalling US$3041 in the Pacific.

Within this, four Asian countries, three in the Americas, eight in the Caribbean - where averages are weighted heavily by the tax havens - 14 of the 18 African member nations, and all of the Pacific states have per-capita GDPs of less than US$10,000.

Extreme poverty afflicts Malawi, Sierra Leone, Tanzania, Zambia and Kiribati, where per-capita GDP slumps below US$1000. Life expectancy in these countries is less than 45 years.

And a new, severe, curse is draining human potential even further. HIV/Aids is fast impacting not only on a rapidly rising number of victims, but on economic growth and national stability. In Nigeria, 3.6 million people live with a disease that killed 310,000 people in 2003; in Sierra Leone 7 per cent of adults are infected; in Tanzania 160,000 people died of Aids in 2003; in Zambia, where 920,000 people are living with it, Aids has hauled life expectancy down to 37 years.

The British charity Save The Children this week reported that 9 million African children had lost their mothers to the disease.

And violence continues to simmer within the family: India and Pakistan are speaking again, but Kashmir continues as a potential powder keg; Sri Lanka has yet to fully reconcile Sinhalese and Tamils, whose 20-year war killed tens of thousands; and Sierra Leone is again teetering on the brink after its brutal decade-long civil war; trouble in neighbouring countries could spill thousands of refugees into northern Ghana.

For now, though, the sun is shining on the Commonwealth in Melbourne.