Shark cage diving has been ruled as an offence under the Wildlife Act.

The Court of Appeal has ruled shark cage diving is an offence under the Wildlife Act, a move being welcomed by paua divers.

Paua Industry Council chief executive Jeremy Cooper said shark cage diving "should never have been allowed to happen from day one", but it was great it was now an offence.

"It makes absolute sense, you know, people's safety and changing shark behaviour has been well documented now so let's hope that's the end of it," Cooper said.

The decision brings a long legal battle between a group of paua divers from Stewart Island, the Department of Conservation (DOC) and shark diving companies, Shark Experience Ltd and Shark Dive New Zealand Ltd.

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* DOC gives Stewart Island shark cage-diving a tick

* Shark-diving conflict in southern seas continues

* Paua divers should steer clear of shark infested waters

The Court of Appeal decision also found that the director-general of conservation had no power to authorise shark cage diving, according to RNZ.

ANDREW GORRIE/STUFF Paua Industry Council chief executive Jeremy Cooper pictured in 2008. He's welcomed the news that shark cage diving is an offence under the Wildlife Act.

Shark diving began near Stewart Island in late 2007 in waters where great white sharks are common due to the large number of fur seal colonies.

As it became more popular, it caused issues.

Some people were worried the sharks were becoming more dangerous.

On the other hand, one shark-diving operator said he had received death threats and began carrying a rifle on his boat.

The paua divers from Stewart Island, PauaMAC5 called for a moratorium on shark cage dive operations, Stuff reported in late 2014.

At the time, DOC was considering applications for cage dive operations in the waters around Stewart Island.

PauaMAC5 said issues should be issued with the safety of other water users in mind, but DOC refused, saying public safety was outside its obligations under the Wildlife Act, RNZ reported.

In October 2016, PauaMAC5 was in the High Court at Wellington making a bid to have DOC consider public safety when licensing cage diving.

PauaMAC5 argued the cage diving, whose operators used bait such as berley or chum to attract the sharks, had deterred swimmers and fishers from entering the water due to fear of attacks.

STUFF Paua divers called for DOC to regulate shark diving in 2013

The group also argued regular cage diving was potentially having a behavioural effect on sharks in the area, resulting in a risk to human life.

By late 2016, DOC was under fire from both sides of the issue as it re-issued temporary permits for operators off Stewart Island.

Cage dive operators were unhappy with confusion over the permits while a member of PauaMAC5 claimed the permits were "simply legitimising illegal activity".

The issue over DOC granting permits went to the High Court in 2017 where Justice Karen Clark found DOC had no basis to give permits in the first place.

PauaMAC 5 did not get what it wanted - a declaration that DOC had to account for peoples' safety when granting permits.

Shark cage diving then went to the Court of Appeal, before the latest ruling.

Stuff has contacted Shark Experience and Shark Dive New Zealand for comment.