Regional Development Minister Shane Jones is being accused of breaching parliamentary rules by appearing to support a fishing company that's facing prosecution for illegal fishing.

New Zealand First MP Mr Jones described the Ministry for Primary Industries (MPI)'s case against agribusiness company Talley's as a "technical issue" - when the Cabinet rules warn ministers against commenting on active cases.

Mr Jones is currently prepping for Waitangi, and in traditional style it'll involve fresh kaimoana (seafood) and a party at his place.

But Mr Jones is now facing criticism for getting too close to the Talley's case, calling it a "mere technical issue which would be ironed out when common sense prevails".

On Friday he changed tact: "They are highly technical matters... and no doubt the court will be possessed of all the information."

Greenpeace executive director Russel Norman said it's "completely unacceptable for a Cabinet minister to intervene in an active court case where the Crown is taking Talley's to court for environmental damage".

The Amaltal Apollo, a vessel owned by a subsidiary of Talley's, is facing 14 charges for fishing in protected waters in the Tasman Sea.

And Cabinet rules clearly state: "Ministers do not comment on or involve themselves in the investigation of offences or the decision as to whether a person should be prosecuted."

"I think there's no question that Jones has breached the Cabinet Manual, which is the rules that govern the behaviour of Ministers," Mr Norman said.

Talley's donated $10,000 to Mr Jones' 2017 campaign. And while Mr Jones accepts that, and that he's mates with Talley's boss, Sir Peter Talley, he says it doesn't mean anything.

Instead, he's blaming Greenpeace for spreading what he calls "misinformation".

"I care not one jot of what that fake environmental body Greenpeace says," Mr Jones said.

Mr Jones has previously been chair of Sealords and held top positions within Māori and Pacific fishery organisations.

He makes no secret of his continued close relationships with the big commercial fishing companies.

It'll be up to the Prime Minister to decide whether Mr Jones has overstepped the mark and breached the rules in this case.

Newshub.