Prime Minister John Key is scheduled to land in Trinidad late tonight for the Commonwealth summit, where United Nations Secretary-General Ban Ki-Moon will make a personal plea for leaders to also attend climate talks in Copenhagen in 10 days.

United States President Barack Obama yesterday said he would attend the start of the talks and that the US emissions reduction target would be 17 per cent of 2005 levels by 2020. Wen Jiabao, the Chinese premier, also said he would be attending.

Mr Key was last night sticking to his position that he is unlikely to go, but he has left the door open.

Asked what it would take, he said "If I thought a deal was going to be concluded, and at this stage it seems very unlikely."

He was speaking in Hawaii on his way to Trinidad.

Mr Key's RNZAF flight, with the leaders of three other countries, Tonga, Samoa and Vanuatu, was delayed several hours as checks were made to a suspected fault in the Boeing 757 carrying their delegations and reporters.

The summit is likely to be dominated by climate change and pre-Copenhagen diplomacy.

In a highly unusual move, French-Anglo rivalry is taking a backseat as French President Nicolas Sarkozy is tipped to make an appearance at the meeting of 53 countries after attending a special meeting of eight Amazon countries in Brazil.

He will join Denmark's Prime Minister Lars Lokke Rasmussen, Mr Ban and UN climate change chief Yvo de Boer in a session on climate change.

In some respects it may be a rerun of the Apec summit in Singapore two weeks ago, where Mr Rasmussen briefed 21 leaders before talks he will host in Copenhagen in 11 days for a treaty to succeed the Kyoto protocol.

The bloc of countries in Trinidad won't be as high-powered as Apec, but with 53 member it is still a large and important grouping, many of whose small island members are most affected by climate change.

The aim of the Rasmussen sessions is to adjust expectations of what can occur at Copenhagen - not that an agreement can be concluded there but that it is the first of a two-step process.

Small developing countries are not expected to make binding commitments in the agreement, but some commitment is expected from the large developing countries including India which is a Commonwealth member.

Commonwealth Secretary-General Kamalesh Sharma in speech in Trinidad this week described this Chogm as a "crisis summit".

"How times have changed since the last People's Forum in Kampala, Uganda," he said.

"We have all had a bad few years: of crisis upon crisis. The fuel and food crises of last year have been compounded by a financial crisis in 2009, in which no less than half of our members are suffering negative growth.