Former New South Wales premier Bob Carr is throwing his support behind a cross-party campaign to end dolphin captivity across the state.

MPs from Labor, the Animal Justice Party and the Greens are working together to draft a bill to end the practice of keeping and breeding dolphins.

In 1986 as a minister in Neville Wran's government, Mr Carr introduced legislation that banned the capture and display of wild dolphins.

But it is still legal to keep and breed dolphins that were born in captivity or rescued after being beached.

There are currently five dolphins being kept at Dolphin Marine Magic in Coffs Harbour.

Mr Carr, who is also the former foreign minister, said it was time the practice ended.

"They're magnificent creatures," Mr Carr said.

"Some said dolphins are the only animals that are friendly to humankind for their own sake. They're sociable.

"To think of these creatures being confined in a pool one third the size of an Olympic swimming pool is to know what this is all about — it's plain cruel.

"We think the crooked smile on the face of a dolphin shows they're enjoying captivity but the captivity is in fact driving them mad."

Dolphin Marine Magic shareholder backs end to captivity

Under the current NSW guidelines, five dolphins can be legally kept in a 1,400-cubic-metre pool.

Mr Carr said when he introduced the legislation to ban the capture of wild dolphins in the 1980s the move did not have broad public support.

But he said now the public was much more aware of the issue.

"Today polls show that Australians find it repugnant to take these magnificent creatures and keep them in prison in pools for our entertainment," he said.

The push to end dolphin captivity also has the support from the founder and now major shareholder of Dolphin Marine Magic in Coffs Harbour.

Hec Goodall started the park in the 1960s because he said he was concerned about stranded animals being without help.

It was developed as a tourist attraction to cover the costs of the care of the animals.

Mr Goodall wants to ensure the dolphins are not just returned to the wild which he said "has happened on a number occasions and turned out to be a disaster".

"I firmly believe there is a better way of exhibiting and caring for them in large sea pens," he said.

Dolphin Marine Magic declined to make a statement but said it would release a reply in due course after the board discussed its position.