BEIJING - A total of 42,800 complaints filed by consumers were against unlicensed vendors in 2011, China's market supervisor said Thursday, which marks International Consumer Rights Day.

The figure accounted for 15.82 percent of total cases filed last year, the most among all other cases, the State Administration of Industry and Commerce (SAIC) said.

The figure was followed by cases violating quality laws and regulations (22,000), and cases infringing consumer rights (14,200), the SAIC said.

"The data shows that unlicensed business activities and breach of quality laws and regulations are still issues of the most public concerns," a SAIC official said, adding that more efforts will be made to smash the illegal practices this year.

The SAIC received 270,500 complaints last year, an increase of 12.16 percent year-on-year. Violations of contract laws and regulations increased the most, up 332.18 percent.