BEIJING - The government has strived to better protect migrant workers' rights and interests by upping minimum wage standards and helping them claim back salaries, said a human resources spokesman on Thursday.

In the first quarter of 2013, eight provinces increased minimum wages for migrant workers, by 13.8 percent on average, Yin Chengji, spokesman for the Ministry of Human Resources and Social Security, said at a quarterly news conference.

South China's economic hub of Shenzhen has the highest minimum monthly wage of 1,600 yuan ($257), while Beijing has the highest minimum hourly wage of 15.2 yuan, according to Yin.

Before the Spring Festival holiday that fell in February this year, a ministry crackdown helped more than 1.67 million workers claim salaries and compensations denied to them by unscrupulous employers, Yin said. The salaries and compensation totaled 8.75 billion yuan.

Migrant workers are often victimized by such defaults, particularly around the holiday celebrating the Chinese Lunar New Year, when most migrants call time on a year of hard work and return to their hometowns for family reunions.

Yin said the ministry has cooperated with the Supreme People's Court in making a judical interpretation that intensifies punishment for wage defaults.

According to the interpretation enacted in January, employers may face a prison sentence up to seven years if they refuse to pay employees by threatening to use or actually using violence.

It also reinforced inspections on employing units to check the implementation of various labor protection laws, the spokesman added.

He said the ministry received nearly 160,000 labor dispute cases nationwide in the first quarter of 2013, up 8.5 percent year-on-year and involving 214,800 laborers.

Yin also said the ministry will promote the urbanization of rural people by including them in the country's social insurance systems, which can guarantee their subsistence in cities.

A total of 486 million people have been covered by the new endowment insurance systems for rural and urban citizens as of the end of March.

The gross revenue from China's five basic social insurances has hit 715.52 billion yuan, with 133 million senior citizens getting pensions every month, according to Yin.