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SYDNEY - The salvage effort for the stranded coal carrier Pasha Bulker is in jeopardy after a second tow line snapped early this morning.

The line to the Queensland supertug Pacific Responder snapped with an explosive crack just before 7am (9am NZT).

Last night a line to the smaller tug Keera snapped.

The Pasha Bulker is now secured only by a line to a third tug, the Woona, and lines to three sea anchors.

Earlier today, NSW Ports Minister Joe Tripodi said gale-force winds today were expected to help the attempt to refloat the Pasha Bulker.

The 40,000-tonne coal carrier has been stuck on a sandbank outside Newcastle since it ran aground in a severe storm on June 8.

Tripodi told journalists there had been unexpected good news overnight.

"The ship has moved now to be nine degrees from its original position," he said.

"There's extra buoyancy as a consequence of air pressure continuing to be put into the ship.

"It's expected there will be gale-force winds today, but they're west-south-west winds, which will favour the operation."

Tripodi said work would continue today, but there was no chance of a second attempt to pull the ship to sea before tonight's high tide around 7pm.

Parts of Newcastle's CBD will continue to be cordoned off, keeping sightseers from anywhere near the salvage operation.

The ship has around 700 tonnes of fuel and 100 tonnes of other chemicals on board, which have prompted worries over a serious breach of the vessel's hull.

Newcastle Port Corporation chief Gary Webb said yesterday there was a hole in the ship's hull, but its size would not be known until the vessel was pulled out to sea and divers could inspect the damage.

Greenpeace protestors last night used a laser light to project the slogans "This is what climate change looks like" and "Coal causes climate chaos" onto the stricken vessel's damaged hull.