Advent Energy, through its subsidiary company Asset Energy, plans to begin drilling in the first half of December.

Advent executive director David Breeze confirmed yesterday that the company had secured state approval from the NSW Industry and Investment Department.

Mr Breeze said the company was awaiting approval from the federal environment department.

He was "very positive" about the prospect of finding gas, saying an independent report found gas was "highly likely at the target drilling depth".

Drilling will take up to 30 days in 143 metre-deep water, with a well depth of 826 metres.

Lake Macquarie councillor Phillipa Parsons, who leads a coalition of groups opposed to the drilling plan, said there had been a lack of community consultation.

Cr Parsons said members of the community consultative committee that the government established for the project had not been provided with copies of the environment plan and oil spill contingency plan.

She said the industry was "grossly under-regulated".

Mr Breeze said Australia had a strict regulatory regime and a good record of success and safety for gas drilling.

Environmentalists were concerned about the potential for an oil spill and damage to the coast and marine life.

Cr Parsons said she was concerned the state and federal governments "consider this is a risk worth taking".

Mr Breeze said the company was confident the risks would be adequately addressed.

Cr Parsons said gas was "not a clean, renewable energy source", but Mr Breeze said it was much cleaner than coal.

Preliminary studies estimated 13.2 trillion cubic feet of gas worth $50 billion was in the company's offshore petroleum licence area from Newcastle to Wollongong.

The drilling could lead to a natural gas industry with the potential to create tens of thousands of jobs and generate billions of tax dollars for government.