Chinese President Xi Jinping offered another $60-billion in financing for Africa on Monday and said Chinese companies will be encouraged to invest no less than $10-billion over the next three years, but he also warned against "vanity projects".

Speaking at the opening of a major summit with African leaders, Xi promised development that people on the continent could see and touch, but that would also be green and sustainable.

China has denied engaging in "debt trap" diplomacy, and Xi's offer of more money comes after a pledge of another $60-billion at the previous summit in South Africa three years ago.

Xi, addressing leaders at Beijing's Great Hall of the People, said the new $60-billion will include $15-billion of aid, interest-free loans and concessional loans, a credit line of $20-billion, a $10-billion special fund for China-Africa development, and a $5-billion special fund for imports from Africa.

Chinese companies will be encouraged to invest no less than $10-billion in the continent in the next three years, he said.

"China-Africa cooperation must give Chinese and African people tangible benefits and successes that can be seen, that can be felt," Xi said.

Chinese officials have vowed to be more cautious to ensure projects are sustainable. China defends continued lending to Africa on the grounds that the continent still needs debt-funded infrastructure development.

Speaking earlier at a business forum, Xi said China had to be careful about where money was spent.

"China's cooperation with Africa is clearly targeted at the major bottlenecks to development. Resources for our cooperation are not to be spent on any vanity projects but in places where they count the most," he said.

Beijing has also fended off criticism it is only interested in resource extraction to feed its own booming economy, that the projects it funds have poor environmental safeguards, and that too many of the workers for them are flown in from China rather than using African labour.

Xi told business leaders Chinese firms in Africa had to be aware of their social responsibilities and make sure their investments served the community and improved their wellbeing.

"I hope that our entrepreneurs will act to fulfil social responsibilities and respect local culture and tradition," he said.

"I also hope you will do more in staff training and bettering lives for the local people and will put more emphasis on the environment and resources," Xi said.

'AFRICA KNOWS BEST'
Chinese officials say this year's summit will strengthen Africa's role in Xi's Belt and Road initiative to link China by sea and land with Southeast and Central Asia, the Middle East, Europe and Africa through an infrastructure network modelled on the old Silk Road.

Xi said the plan, for which Beijing has pledged $126-billion, would help provide more resources and facilities for Africa and would expand shared markets.

China loaned around $125-billion to the continent from 2000 to 2016, data from the China-Africa Research Initiative at Washington's Johns Hopkins University School of Advanced International Studies shows.

State media has accused the West of sour grapes over China's prominent role in Africa and has angrily rejected claims of forcing African countries into a debt trap.

"In terms of cooperation with China, African countries know best," widely read tabloid the Global Times wrote in an editorial on Monday.

"Western media deliberately portray Africans in misery for collaborating with China and they appear to have discovered big news by finding occasional complaints in the African media about Sino-Africa cooperation," it said.

Every African country is represented at the business forum apart from eSwatini, self-ruled Taiwan's last African ally that has so far rejected China's overtures to ditch Taipei and recognise Beijing.

African presidents in attendance include South Africa's Cyril Ramaphosa, Egypt's Abdel Fattah al-Sisi, Zambia's Edgar Lungu and Gabon's Ali Bongo.

There are some controversial guests. Sudan President Omar al-Bashir, who has been in power for nearly 30 years, is wanted by the International Criminal Court (ICC) for war crimes over killings and persecution in Sudan's Darfur province between 2003 and 2008.

Xi told him on Sunday that "foreign forces" should not interfere in Sudan's internal affairs, China's Foreign Ministry said. China is not a party to the court.

"China has always had reservations about the International Criminal Court's indictment and arrest order against Sudan's president. We hope the ICC can prudently handle the relevant issue," Foreign Ministry spokesperson Hua Chunying told reporters.