Through the Bob Brown Foundation, he's taking on the state-owned logging group Sustainable Timber Tasmania, as well as the state and federal governments.

In a Federal Court hearing on Wednesday, his lawyer Ron Merkel QC said he had been instructed earlier in the day to seek an urgent injunction against planned logging activities that could harm the swift parrot.

The bird is critically endangered.

"The problem with that particular species is that the breeding season starts in September and goes through to January - the next three months are critically important," Mr Merkel said.

Under commonwealth guidelines, any real possibility or chance of disruption to a breeding cycle is regarded as a significant impact, he said.

In the primary case the foundation is arguing Tasmania's regional forest agreement is invalid because it doesn't include a legally enforceable requirement for the state to protect threatened species.

Mr Merkel said if its case was correct then any logging carried out would be done in way that could endanger a species without approval.

The foundation is arguing its case through concise statements, rather than the more detailed pleadings usually provided.

Anna Mitchelmore, representing the Commonwealth, said she had ongoing concerns about the sufficiency of the allegations being made in that statement.

Tasmanian Solicitor-General Michael Farrell also pushed for detailed pleadings to be provided.

"We're entitled to understand the case put to us," he said.

But Federal Court Judge Duncan Kerr said the case was "not that difficult to understand" and suggested starting from the beginning with fresh pleadings "takes you nowhere".

The whole point of the concise statements was to avoid unnecessary technicality, he said.

He's giving the parties until Monday to resolve the issues themselves and file any new documents before another directions hearing next week.

Australian Associated Press