Reports suggested overtime at Portsmouth Dockyard was to be cut by as much as 75 per cent.
The cuts would affect all 11,500 workers at the yard.
The overtime restrictions were an economy measure by dockyard management to keep within budget limits.
A dockyard spokesman said the regulation of overtime was used at the yard to keep within budget limits and was normally applied or eased off according to available money and priorities.
This time, however, the cutback on overtime was being applied more drastically.
L Brooks, of the Dockyard Whitley Council, said there had been close co-operation between management and unions on the issue, and the question of overtime would be revised at reasonably frequent intervals.
He said despite circulating speculation, official restriction figures had not been released.