A union official said the truss could have been removed as early as Tuesday had inclement weather not put the operation on hold.

Two cranes are in place - one of 350 tonnes and another of 500 tonnes - waiting to remove the truss in two pieces.

Workers used hydraulic fasteners to loosen bolts on the roof yesterday in preparation for the roof structure to come down.

Mick Lane from the Construction, Forestry, Mining and Energy Union said if the weather lifted, he expected the roof to be on the ground by the weekend.

‘‘If you’d asked me on Monday, I’d have thought they would have had it down by now,’’ he said.

‘‘They were going to try as early as last weekend, but the weather and wind prevented that.’’

State ministers Greg Pearce and Graham Annesley announced last month that the western grandstand would be open by early June, allowing the St George Illawarra Dragons to play six games during the 2012 season.

The nearby Steelers Club has been hemmed in by the repair works, which has hurt its business.

Chairman Peter Newell said he wanted the matter resolved quickly.

‘‘Sooner the better, as far as we are concerned,’’ Mr Newell said. ‘‘We don’t like the perimeter of our club being a building site any more than the builders like being there.’’