The officials said the summit might be held a week earlier than planned because world leaders and other delegates may be unwilling to fly to South Africa around the time of the anniversary of the suicide plane attacks on New York and Washington.

South African officials have been reluctant to discuss security arrangements for the summit in Johannesburg and say there has been no specific threat.

Business Action for Sustainable Development (BASD), international business arm of the summit, said in a statement issued from Paris that a decision on summit dates was likely by mid-December.

DISCUSSIONS ON POSSIBLE CHANGE

The group said Dutch Environment Minister Jan Pronk had been nominated as U.N. Special Envoy for the summit and was talking to governments about holding the conference a week earlier than planned in order to avoid September 11.

"It is understood that one favoured option would be August 26 to September 4," BASD said.

A South African Foreign Ministry official confirmed the date was under review, saying: "The matter is still under discussion."

A government source, who declined to be named, said however that South Africa had accepted the proposed shift to a September 4 close, adding that the new timetable was likely to be ratified within weeks.

The September 11 attacks have hit other aspects of planning for the summit, including corporate funding.

Tokyo Sexwale, chairman of the South African Business Coordination Forum, told Reuters his group would meet Environment Minister Valli Moosa on Friday to discuss business contributions for the summit, offically expected to cost up 550 million rand ($53.9 million).

Moosa told reporters earlier this week he expected foreign governments and corporate sponsors to cover substantially more than half the cost of the summit, but so far he had firm commitments from governments for only 70 million rand.

"Following our presentation to the government tomorrow and after we have all applied our minds, I think we should be able to ascertain where the situation of funding lies," Sexwale said.

"The terrible events of September 11 have destablised the whole world.... This is something we have to discuss with the government," he said.

A source with one of the organising groups said business felt Moosa wanted too much from them and that the global economic decline since September 11 had undermined their ability to contribute what they had promised before the attacks.