But official forecasts show that NSW will be unable to supply its own power needs for at least a week and union officials say they are under intense pressure from rank and file members to increase the level of industrial action.

Unions NSW spokesman Peter McPherson said workers were calling for a single statewide mass meeting early next week, which would leave the state's three power companies, Delta Electricity, Eraring Energy and Macquarie Generation, on skeleton staffs.

Mr McPherson said power workers were so incensed by the Government's actions on privatisation that he could not rule out the industrial action spreading to power workers in the transmission and distribution sectors of the industry, which will remain in government ownership.

He said workers at Vales Point and Wallerawang power stations voted to temporarily lift the overtime ban to ensure the power stayed on, but there was a great deal of debate.

As The Herald reported yesterday, Delta had five of its eight generating units out of service and unable to be quickly repaired because of statewide union bans on power industry overtime.

MacGen had one unit out of service on planned maintenance at Liddell, near Muswellbrook, and had to cut the output of the remaining three units because heavy rain soaked coal stockpiles, leading to blocked and broken coal conveyors.

At a NSW Industrial Relations Commission hearing yesterday afternoon, Delta's industrial relations manager Errol McLachlan said maintenance workers had agreed to work overtime to put Vales Point No 6 into service, hopefully over the weekend.

National Electricity Market Management Company forecasts for the coming week show the state's power shortage peaking on Tuesday, with demand likely to peak at 11,255 megawatts and the state's power stations able to supply 8970 megawatts.