The council made the comment in a submission to the NSW government about Advent Energy’s plans to begin exploratory drilling next month for natural gas 55 kilometres off Newcastle.

As reported on Monday, the company’s environment plan lists four scenarios that could cause an oil spill, including a refuelling incident, collision, subsea blowout and subsea rupture.

The company has maps of possible oil spills in its environment plan.

One of the maps shows oil could spread from Newcastle to Sydney 11 weeks after a spill initially takes place.

‘‘This is extensive and would effectively impact the entire east coast of NSW, including Lake Macquarie, to Victoria,’’ the council’s submission said.

It said the threat of oil polluting Swansea Channel and the lake ‘‘adds to the concern over impacts on coastal and ocean environments’’.

‘‘The lake is poorly flushed and pollutants are easily trapped.’’

Advent’s oil spill risk assessment said spills were rare, but ‘‘it is recognised that there is a potential for oil spills to have a significant impact on sensitive marine environments’’.

The company prepared an oil spill contingency plan.

‘‘Both drilling and rig operators are experienced operators and have an excellent performance reputation with environmental management,’’ the company said.

The council’s submission said a severe storm could cause an oil spill.

It said the company’s analysis ‘‘must include severe weather-induced incidents resulting in a leak where pollution is driven towards the shore’’.

The company’s risk assessment included analysis of meteorological conditions, including an east coast low.

Recent oil spills off Western Australia’s north-west coast, the Gulf of Mexico and Dalian, China, highlight the damage an oil leak could cause, the council said.

The council said Advent’s plan was inconsistent with the federal government’s plan to establish marine reserves off the Hunter coast.