"China equals Hitler" said the sign held up in the Zambian capital Lusaka by a protester opposed to Beijing's tightening grip on the economy of the southern African nation.

The demonstrator, James Lukuku, who leads a small political party, was picked up by police and spent several hours in a cell reflecting on his one-man protest.

But he is not alone in opposing China's growing presence in President Edgar Lungu's Zambia and in particular its major programme of loans to Lusaka.

In fact his criticism echoes concerns shared by many across swathes of Africa and beyond, where some fear that China's mega-projects risk leaving already fragile economies in even worse shape.

"I want to bring to the attention of the international community the Chinese influence and corruption in Zambia," said Lukuku who wore a white T-shirt emblazoned with the slogan #sayno2China.

China is the main investor in Zambia as it is in several other African countries and with its offers of "unconditional" aid, most public tenders are awarded to Chinese bidders.

In Lusaka and across the country, China is busy constructing airports, roads, factories and police stations with the building boom largely funded by Chinese loans.