The company last month revealed its plans for the proposed high efficiency, natural gas fired plant and associated gas transmission pipeline.

The EES will be on display and open for public comment until January 12. A decision about whether the project proceeds is expected in the second half of next year.

"The EES reflects the detailed and comprehensive work by our project team and specialist consultants as well as consultation with the local community and landowners who live near the proposed power station site and gas pipeline route," Origin general manager of public and government affairs Tony Wood said.

The project would be developed using natural gas from reserves in the Otway Basin and would boost Victoria's base load generating capacity by 12%.

If this station were running today, it would probably not be cost-competitive as base-load electricity can be produced about 30% cheaper from brown coal reserves than from natural gas.

The Victorian Opposition has argued for cost-effective power while the Government has argued for jobs and clean energy, but Origin expects to achieve all of these objectives.

Origin managing director Grant King said this year that the company expected the national electricity market to move over the next few years from a position of significant oversupply to a state in which investment in additional base-load electricity generation plants was needed.

Origin won't complete the project until 2008 at the earliest, and believes that the plant will be cost-competitive by then because gas generation technology will improve, environmental costs associated with coal-fired generation will rise, and natural gas will become relatively cheaper..

"Undertaking the development approval and community consultation processes now will provide Origin with greater flexibility in responding to market conditions as they evolve," he said.

Origin has also said that using natural gas to fuel power stations provides many benefits including lower greenhouse gas emissions, as well as greater flexibility in operating arrangements during the week.

After the January deadline, an independent panel will review the EES and prepare a report to the minister for planning.

The minister will then consider the panel report and prepare a formal assessment under the Environment Effects Act.

A similar project at Spring Gully in Queensland is undergoing state approvals, after its environmental impact statement was released last weekend.

The Mortlake EES can be viewed at www.originenergy.co.au/vicgenproject