BEIJING, March 7 (Xinhua) -- China has pledged to eradicate crimes related to delaying or denying salary payments before 2015, a prominent source of complaints for migrant workers, Yin Weimin, minister of human resources and social security, said Wednesday.

Wage delays have been a perennial headache for hundreds of millions of migrant workers, who often lack formal contracts and are sometimes left unpaid after their companies report low earnings or declare bankruptcy.

Such cases, however, have seen a yearly decline in number, and the trend should end before the 2011-2015 period is complete, Yin said at a press conference held during the country's ongoing legislative session.

Yin said China has implemented several measures to tackle the problem, including writing "intentional delay of salary payments" into the criminal law last February.

"Over the past year, Chinese police have handled more than 300 such cases and taken over 200 of them to court," Yin said.

An advanced payment mechanism and a requirement for "guarantee money" from construction companies have also been created by the government in response to complaints about wage delays.