Qatar has reportedly slashed its budget for hosting the 2022 FIFA World Cup by up to 50 percent.

The Gulf state, which had planned for 12 stadiums in its original bid, is now proposing eight, it was reported.

Hassan Al Thawadi, secretary general of the Supreme Committee for Delivery & Legacy organising the tournament, told CNNMoney the original budget had been reduced by between 40-50 percent.

"We wanted to ensure there is financial responsibility in relation to the infrastructure relating to the World Cup," he was quoted as saying.

CNNMoney reported tournament infrastructure will cost between $8-$10 billion, with most of the money earmarked for stadiums and training grounds.

It quoted Al Thawadi as saying that FIFA has not yet agreed on the final number of stadiums needed for the tournament but if it accepts Qatar's proposal, the World Cup will be played in the fewest stadiums since Argentina hosted the tournament in 1978.

On Wednesday, a report claimed migrant World Cup stadium labourers in Qatar can work 18-hour days - more than twice the maximum amount permitted by law.

Half of the 10 contracting companies surveyed in the compliance report failed to give their employees even one day off per week.

In the most extreme example, some labourers worked 148 days in a row, equivalent to five months without a day off, the study by London-based Impactt found.