The Rugby World Cup in 2011 will be the biggest event to come to New Zealand and our best chance in a generation to brand ourselves on the world stage as clean and green. With the prestige of hosting the cup come huge economic benefits.

But the event also carries huge risks to our important and valuable brand if we are seen to drop the ball on sustainability.

Imagine what it is likely to look like. An estimated 60-70,000 visitors are expected to fly to New Zealand for the cup. A return trip from Britain to New Zealand emits 7.6 tonnes of carbon dioxide - about the same as the per capita emissions of a Swedish citizen over a year.

Many will be looking to the New Zealand Government to reassure them that we're serious about our response to climate change. In an age when driving an SUV is akin to wearing fur we will have to make a special bid in climate-change terms for them to feel good about travelling to New Zealand.

Cup fans will arrive at Auckland International and find they can't simply catch a train to town but will have to pile into a bus or mini-van and experience Auckland's notorious motorway. They'll discover New Zealand's transport systems are still heavily car-reliant, with few public-transport options in the towns and none at all in smaller centres.

They'll find most of the houses are cold, damp and poorly insulated, with hardly any solar hot-water heaters. Flicking the switch, they'll find old-fashioned, wasteful light bulbs that the Government recently stopped being phased out.

Piling into the refurbished Rugby World Cup stadium in Mt Eden they'll grab a temporary seat and look around and find it has been expanded on a shoestring budget, with no recycling and no consideration given to its carbon footprint.

The visitors will be stunned that people are still wasting energy, driving their cars too often, and who make excuses about their huge ecological footprint.

If they look into it, they'll find our greenhouse-gas emissions have increased 26 per cent since 1990. They'll feel cheated by the marketing slogans when they find their expectation of "Clean and Green New Zealand" shattered.

The Rugby World Cup could show up New Zealand as an international environmental embarrassment to an increasing environmentally conscious global public. The lingering hangover from such exposure could taint our waters for years. Our brand is vitally important to our economy and we can't afford to put that reputation at risk, especially in a recession.

However, we still have close to 1000 days until kick-off and we can still turn the cup into a showcase. So who in New Zealand is thinking about "sustainability" and "rugby" in the same sentence and are there plans to do deal with these important questions?

The apparent answer is "hardly anyone" and "not really". A Rugby World Cup 2011 Government Co-ordination Office has been established within the Ministry of Economic Development but sustainability is glaringly absent from their objectives and publications.

The Ministry for the Environment is developing an environmental sustainability strategy for the cup but, worryingly, they only point to the $4.6 million LOVENZ programme to see 600 recycling bins around New Zealand as their only practical example.

With New Zealand in the spotlight, Kiwis need to be worried about protecting our brand but also excited about the opportunities. The thinking behind a Green New Deal and President Obama's investments in renewable energy and green jobs shows that sustainability can be a boon for the economy.

If we really took the opportunity of the cup we could invest in our transport infrastructure to get people around faster, more comfortably, and with less oil. Using easy alternatives, we could reduce our greenhouse-gas emissions and save money.

Like France's World Cup Saint Etienne Stadium, Eden Park could produce its own power from roof-top solar panels, with energy-efficient lights and use recycled water for its playing surface. A modern, sustainable cheap-to-run national stadium would make a great cup legacy.

The Rugby World Cup could add the urgency for a raft of cost-effective, job-producing green initiatives.

We can't just talk about it any more. We need to pressure the Government to start making a reality of "Clean and Green New Zealand". The worst outcome would be waking up the day after the final with a mess to clean up and nothing to show for the party.

* Gareth Hughes is an environmentalist who has worked for Greenpeace and the Green Party.