Melamine-tainted leftovers from the 2008 dairy scandal have been resold by five manufacturers, Chinese Health Minister Chen Zhu said at a national teleconference in Beijing on Saturday, Xinhua news agency reported.

Despite a crackdown by health agencies in 2009, at least five companies are believed to have resold products linked to the milk scandal which left six babies dead and 300,000 people sick.

The minister urged a thorough investigation of the dairy market nationwide to cleanse the leftover products contaminated by melamine, an industrial chemical that leads to kidney stones and renal failure, especially among young children.

Lei Yulan, Deputy Chief of south China's Guangdong province who attended the emergency meeting in Beijing, confirmed on Monday that part of the recalled dairy products in 2008 had trickled back into the market, without offering further details on its quantity and range.

The health department in the province is working on a food safety campaign focusing on the dairy market.