Central African states Gabon and Burundi placed curbs on the sale of Chinese milk products after a contamination scandal which has killed four children in China.
Gabon banned the import and sale of Chinese powdered milk, while Burundi told importers and traders to suspend sales of all milk products from China.
They join a number of states in Asia and Africa which have declared a health alert over the tainted Chinese milk powder that has made thousands of Chinese children ill.
The powder was found to be contaminated with melamine, a compound used for making plastics.
Gabon's Trade and Industrial Development Minister Paul Biyoghe Mba prohibited the sale and import of milk powder for babies, including that produced by two Chinese companies, Guangdong Yashili Group Co Ltd and Qingdao Suncare Nutritional Technology Co Ltd, among others.
Mba's order, published by Gabonese media, said offenders who flouted the ban would be severely punished.
Gabonese President Omar Bongo, Africa's longest serving ruler, has maintained more than three decades of cordial ties with China, which receives some oil from Gabon.
Chinese companies are engaged in major mining and infrastructure projects in Gabon, part of Beijing's aggressive investment drive to lock up energy and raw materials supplies from the African continent.
The ban on Chinese powdered milk products came as a shock to some Gabonese mothers.
"It's difficult to change milk suddenly because I've been buying Chinese milk powder for several months due to its generally reasonable price," said 28-year-old mother of three Melanie Obone in Libreville's Mont Bouet market.