The International Labour Organization said the number of worker complaints more than doubled in a year to 34,425 with the launch of a new online platform, in a report which called on Qatar to bolster the implementation of reforms launched after criticism of its rights record.
"The main causes of complaints concerned non-payment of wages and end-of service benefits, and annual leave not being granted or paid," said the ILO report which added that 10,500 cases went to labor tribunals where nearly all judges ruled in favor of workers.
Qatar, where the World Cup starts on November 20, has been widely criticized over conditions for migrant workers - as well as rights for women and the LGBTQ community.
The ILO report said the number of workers treated for heat related problems linked to the Gulf state's searing summer temperatures had also fallen after the introduction of new restrictions in 2021.
It said four clinics for migrant workers treated 351 workers this summer, down from 620 in 2021 and 1,520 in 2020.
"There is universal acknowledgement that more needs to be done to fully apply and enforce the labour reforms," said the report.
"We all recognize that we are not yet at the finish line, and we will build on this solid foundation to address the gaps in implementation, and ensure that all workers and employers can fully benefit from these major reforms," said Ruba Jaradat, ILO regional director for Arab states.
Rights groups have continued to put a fierce spotlight on Qatar's record, accusing the government of under-reporting the number of deaths on mega construction projects linked to the World Cup and demanding FIFA set up a compensation fund for migrant workers.
The ILO said, in a report issued in 2021, that 50 workers had died on construction projects in 2020.
It has not updated these figures, but its report said "substantial efforts" have been made in "labor migration governance, the enforcement of the labour law and access to justice, and strengthening the voice of workers and social dialogue."
It said more than 300,000 workers had been able to change jobs after the partial dismantling of the "Kafala" labor system that previously meant a worker could not change posts or even leave the country without permission from their employer.
But it added: "There is a universal recognition that the work is not complete. This is not surprising given their (reforms) magnitude. It takes time to build institutions and change deep-rooted practices."