The top US diplomat for Africa said Tuesday that China should act responsibly on the continent as it buys up African oil, gas and minerals to fuel its booming economy.

Speaking after his return from US-China talks on Africa, Johnnie Carson, assistant secretary of state for African affairs, said his message to Beijing is: "Act as a responsible player."

"We hope that as they invest... that they will employ African labour, that they will follow local labour standards, that they will pay decent wages, that they will train their personnel, that they will impart technology," Carson told journalists in Africa on a conference call from Washington.

China-Africa trade soared more than 40 percent last year to $126.9 billion (93.8 billion euros). The country has bankrolled sorely needed infrastructure projects across the continent, but has been criticised for supporting unsavoury regimes.

The growing relationship has at times made the United States uneasy.

Last year, Carson was quoted as saying in a diplomatic cable published by whistleblower website WikiLeaks that China had "no morals" in Africa.

"China is a very aggressive and pernicious economic competitor with no morals. China is not in Africa for altruistic reasons. China is in Africa for China primarily," the cable quoted him as saying.

He said Tuesday that the United States does not see China as an adversary in Africa, but called for Chinese firms operating there to create more local jobs, amid growing concern on the continent over the use of imported workers.

"American companies invest extensively in and across Africa, but they don't bring thousands and thousands of American workers to do unskilled labour jobs," he said.

He also said Beijing needs to help fight corruption.

"We hope that China's engagement in Africa will be responsible, and that they will not engage in bribery," he said.

"It is also very, very important that African countries hold China to the same high standards of operation that they hold American and European countries to."