NSW Greens MP Lee Rhiannon said seismic vibrations could harm whales migrating along the coastline, have a negative economic effect on whale-watch businesses and galvanise community and environmental groups.

"The biggest issue this application raises is the lack of genuine public interaction in government processes that inevitably lead to mining approvals," she said.

Energie Future has applied under the Commonwealth Offshore Minerals Act for four mineral exploration licences that cover a total of 5940 square kilometres from Stockton Bight to Stanwell Park.

Energie spokesman Rick Somerton told The Herald that his company wanted to extract energy from seabed coal in a process called gasification.

It involved injecting air into the coal, igniting an underground fire, extracting gas and piping it to shore, where it could be used to run electricity-generating turbines, converted into a diesel fuel in a coal-to-liquid factory or used as feedstock in petrochemical processes.

A spokeswoman for the NSW Department of Primary Industries said Energie's application was additional to oil and gas exploration off the Newcastle to Sydney coast that has become known as the Bounty [Oil and Gas] project.

Bounty is believed to involve a $4 billion seabed gas reserve that is expected to be tapped by a drilling rig 20 kilometres off Catherine Hill Bay and piped ashore.

Primary Industries officials said yesterday that public comment time for the Energie applications would be extended, as the plan was put on exhibition on Monday without sufficient information to fully explain it.

The application will be considered by state and federal bureaucrats before a final decision is made by federal Resources Minister Martin Ferguson.