Chinese officials are warning Hong Kong to tighten its GM labelling laws in line with the mainland regulations, or risk a flood of genetically modified food imports.

Tough rules endorsed last month by the State Council requires strict labelling of all GM ingredients imported into and sold in China. They are expected to come into force by the end of this year, and Professor Xue Dayuan, a research centre head for the State Environmental Protection Administration, said that those manufacturers who could not meet the requirements are likely to abandon their products in Hong Kong. This is particularly likely given that Hong Kong is an important entreport for food bound for mainland China.

"Since the trade links between [Hong Kong and China] are so close, I can't see how two different labelling systems can operate together," he said.