Toyota is considering a shorter working week as sales slump in the global downturn.
The car manufacturer said it was considering the cut in hours to help slash costs at its factories in Derbyshire and Flintshire.
Night shifts have already been suspended and two 14-day shutdowns are also being planned.
Toyota spokesman Steve Carter said that the measures were necessary to ensure that no jobs were lost among the manufacturer's 4000-plus workforce.
He said: 'Our employees recognise further action is needed to maintain the employment levels at the factory.
'But redundancies are not included in the measures, which have been put forward by the company.'
The cuts in production follow news that Toyota is expected to record its first-ever loss, which could be as much as 1 billion.
The deficit follows a 4% fall in global sales and the company has already announced the postponement of 88 million of investment at its engine plant in Flintshire.