A development in a long-running stoush between shark cage diving operators and paua divers

The Court of Appeal last year ruled the tourist activity an offence.

But today the Supreme Court's decided although it was right the Wildlife Act can cover more than hunting and killing protected species - cage diving isn't illegal.

Shark Experience director and skipper Mike Haines says concerns - mostly from paua divers - the activity causes sharks to behave more aggressively are unfounded.

He says sharks investigating vessels is a natural behaviour.