Qatar's labor minister says there is no timeframe for promised reforms to the 2022 World Cup host's controversial system of tying migrant workers to a sponsoring employer.

The official Qatar News Agency late on Monday quoted the labor and social affairs minister, Abdullah Saleh Mubarak al-Khulaifi, as saying that the energy-rich Gulf nation is committed to improving conditions for foreign workers.

But he says he cannot provide a date for new legislation addressing the kafala, or sponsorship system.

Qatar last May announced plans for a new law that could eventually end the sponsorship system, forms of which are used throughout the fast-developing Gulf states.

Rights groups have urged Qatar to scrap the system, saying it leaves workers open to exploitation and abuse.