Living Ocean, a not-for-profit Palm Beach conservation group that "promotes the awareness of human impact on the ocean", discovered a Perth-based gas company wanted to conduct seismic testing during September in waters 40 kilometres south of Newcastle.

The area of testing would have covered about 208 kilometres and was scheduled during the peak time for the southern migration of humpback whales and their calves.

Asset Energy applied to the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) to do the seismic testing but their application was unsuccessful and the company has been told to modify and resubmit their application.

The director of Asset Energy, Toby Foster, said Living Ocean was involved in constructive community discussions about the company's proposal.

"Living Ocean had concerns for whale welfare and even though we didn't agree with them to some degree as to the impact because of the low scale and low acoustic nature of our proposal, we understood their concerns," Mr Foster said.

"Should we be successful in gaining approval, any exploration we do will be outside peak whale migration period."

Living Ocean president Robbi Newman said the "testing time and location would have been devastating had it gone ahead".

"Once we were notified of the seismic testing application, we were able to share our extensive scientific data with NOPSEMA, as well as carry out meaningful discussions with the gas company", Mr Newman said.

"Asset Energy has taken this all on board and now plans to conduct its testing in the more suitable time frame of January/February 2018, when there are very few whales about."

Sam Barripp, the humpback whale research team leader for Living Ocean, said it was critical that a calf had quality time with its mother during the first 12 months of its life.

"Our main concern was the mums and bubs heading south and bubs only have about 12 months to learn the vital life lessons from their mother so the blasting of massive noise would have been terrible for humpbacks that use sight and sound to survive," Mr Barripp said.

"The noise from this sort of testing would have been like holding a rock concert in a preschool classroom."

Living Ocean has been recording the migratory tracks of humpback whales passing Sydney since 2003, and has been collecting data though an app specifically designed by member Bill Fulton to "safeguard the whales' migratory route against sand mining, fish farms and seismic testing".

Mr Barripp said the group urgently needed donations or access to a boat to ensure they could continue their whale research.

"We have been chartering a boat but the company we use now charges almost double so we need to find another way," Mr Barripp said.