Migrant workers building the first stadium for Qatar's 2022 World Cup have been earning as little as 55 cent an hour.

The pay rate appears to be in breach of the tournament organisers’ own worker welfare rules and comes despite the Gulf kingdom spending €170 billion on infrastructure ahead of the competition.

More than 100 workers from some of the world's poorest countries are labouring in ferocious desert heat on the 40,000-seat al-Wakrah stadium, which has been designed by the British architect Zaha Hadid and is due to host a quarter-final.

Pay slips show they are toiling up to 30 days a month for as little as €6.20 a day. The rates are among the lowest the Guardian found during a week-long investigation into conditions for migrant labourers across Qatar's construction industry, and come despite pledges by the tournament's organisers to make workers' rights "our top priority".

Hadid, whose practice is likely to earn a multimillion-pound fee on the project, said in a joint statement with fellow design firm Aecom that they were “working closely with our clients to ensure that any outstanding issues are resolved”.

Stadium workers also told the Guardian their passports were being held by their manager, in apparent breach of the World Cup organisers' own worker welfare standards which state: "The contractor shall ensure that all workers have personal possession of their passports and other personal documents."

Sponsorship system

Withholding passports has been identified by the

Qatar

government’s own lawyers, DLA Piper, as an abuse of the country’s migrant labour sponsorship system that can contribute to conditions of forced labour.

The problems for the World Cup workers come after the Guardian revealed on Monday that migrant labourers who fitted out luxury offices used by Qatar's World Cup organising committee have not been paid for up to a year and are now living in squalor.

There has been an international outcry over the deaths of hundreds of migrant builders in Qatar in construction accidents and traffic collisions, and from suicides and heart failure. Low pay, late pay and even no pay are now an increasing concern.

Pay slips for workers on the al-Wakrah stadium suggest the contractor is breaching rules on overtime pay and working hours limits set by Qatar’s World Cup organising committee.

One labourer was hired on a basic monthly salary of €170 and worked 64 hours of overtime in April. He was paid just €37 for the overtime, making the overtime rate 57 cent an hour. His basic salary, if he worked the maximum 48-hour week allowed, was 80 cent per hour.

The Supreme Committee for Delivery and Legacy’s worker welfare standards state overtime should be paid at basic wage plus 25 per cent and that the maximum working week should be 60 hours. If the labourer worked on average 16 hours overtime a week as the documents suggest, after a maximum 48-hour week, then he would have worked longer than the allowable maximum of 60 hours.

Another labourer’s pay slip shows he worked every day in April, including 38 hours overtime, for a total salary of €42 per week, or €6.05 a day. Qatar is spending around €3 billion building eight stadia for the World Cup.

Mohamad Ahmad Ali Hussain Hamad, the project manager at Amana Qatar Contracting Company, which employs the workers, said an audit had "identified the need of further clarification with regards to workers' payslips and we are working with the supreme committee for Delivery and Legacy to clear up the same".

The wages are still slightly higher than in the workers’ home countries. Building labourers earn around €4 a day in India and around €5.70 in Nepal, where salaries are rising because of a shortage of labour – partly the result migration to Qatar.

After workers on the stadium told the Guardian their manager had their passports, the World Cup organisers said: "The supreme committee expressly forbids any contractor to confiscate the passports of its workers."

Welfare standards

It said that in the Amana contract, which was under an earlier version of its worker welfare standards, workers were provided with the option of voluntarily, and only with signed consent, handing over their passports to the contractor for safekeeping.

Qatar’s World Cup bosses have ensured that Amana provide high-quality accommodation for the workers on the al-Wakrah stadium.

They live in solid and clean three-storey apartment blocks with no more than three beds to a room and with en suite bathrooms in some cases. Three meals a day are laid on, and living rooms are equipped with flatscreen TVs and wireless internet access. In the block shown to the Guardian there was table tennis, table football and a collection of cricket and football equipment.

A domestic worker launders the workers’ clothes while they are on shift and there is a suggestion box seeking ideas for improvements.

"This is a model of how serious we are in terms of wellbeing," said Stefan Van Dyke, a member of the Qatar 2022 welfare committee. "Once the worker lives well and eats well, he works well. We had to get the contractors to buy into the process and there is a return on their investment. We are being told that they are seeing a lower rate of absenteeism." Guardian Service