Tony Blair has held Downing Street talks with his South African and Canadian counterparts in advance of next month's G8 summit in Kananaskis.

The prime minister met with South African president, Thabo Mbeki, and the Canadian prime minister, Jean Chretien, to discuss how the G8 will respond to the New Partnership For Africa's Development (Nepad).

The Nepad initiative is a US$64 billion aid programme which has been hit by controversy following the re-election of Robert Mugabe in Zimbabwe.

"Obviously the main focus was the preparation for next month's G8 summit in Canada, and in particular the G8 can best respond to the Nepad initiative," said a spokesman.

"The prime minister paid tribute to Jean Chretien's leadership in taking forward the preparations for the G8 but also in his discussions with him talked about the Middle East, the campaign against terrorism and Kyoto."

South Africa has warned the G8 that it should not hold Nepad hostage because of the political situation in Zimbabwe.

"If Nepad is not owned and implemented by Africa it will fail," warned a South African minister. "We cannot be held hostage to political whims of the G8 or any other groups."

Western countries, including the UK, Canada and the US, have threatened to withdraw their support for Nepad following Robert Mugabe's "victory" in the Zimbabwean presidential election.

Downing Street dismissed claims that the prime minister had discussed the situation in Zimbabwe with the two leaders.