Chinese local governments have been told to raise minimum wages to prop up living standards as food prices have climbed this year, said sources with the Ministry of Labor and Social Security on Thursday.

Local governments must do so before the end of the year in regions where minimum wages rise slowly or are markedly lower than average wages, according to a circular issued by the ministry.

The ministry required labor departments across the country to put forward timely schemes for adjusting monthly and hourly minimum wage standards, according to local economic conditions, average wages, consumer prices and employment rate.

Food prices have been on the rise in China this year, pushing the country's inflation rate to 3.4 percent in May compared with a year earlier, higher than the government's warning level of three percent.

Grain prices rose 5.9 percent, meat and poultry 26.5 percent, and eggs 37.1 percent in May, which would have a great impact on low-income families, according to the ministry.

In China, minimum wage standards vary from region to region. By the end of last year, South China's Shenzhen City topped the list with a monthly rate of 810 yuan (105 US dollars), while eastern Jiangxi Province was bottom with 270 yuan per month.

Twenty-nine of the 31 provinces, municipalities and autonomous regions on the Chinese mainland increased their minimum wage standards in 2006.

Shanghai, one of the country's most expensive places to live in, raised its minimum wage by 60 yuan a month to 750 yuan last year.