Long-awaited changes to Qatar's ‘kafala’ labour law for foreign workers will come into force in December next year, media reports said on Friday.

The law reforming rules that oversee exit visas and work contracts in the gas-rich Gulf state was published in Qatar's official gazette.

The Arabic-language Al-Sharq reported that the changes will take effect on December 14 next year, 14 months after first being approved.

This is the first time a definitive date has been given for the new laws to come into force.

The reforms will allow foreign workers wishing to leave Qatar to apply for permission up to 72 hours in advance to the interior ministry.

If such permission is initially denied, employees seeking to leave can then complain to a grievance committee established under the new law.

Currently, workers need an exit visa approved by their sponsor to be able to leave the country.

The changes also allow foreign workers to switch jobs at the end of a fixed-term contract.

Under the current system, workers who leave a job at the end of a contract have to wait two years to return to Qatar to take up a new position, if their old employer objects to the new job.

The system applies to around two million foreigners who make up about 90 percent of the population in the state.

The number of foreign workers, many of them labourers on major infrastructure projects directly or indirectly related to the 2022 FIFA World Cup, is expected to reach 2.5 million by 2020.