A regular cruise ship visitor to the Port of Tauranga may have its next cruise delayed, while an investigation into the death of a crew member on board is carried out.

The man died on Thursday when a gas cylinder exploded on board while the Emerald Princess was alongside at Port Chalmers.

The Emerald Princess arrived at Port Chalmers from Akaroa just before 8am on Thursday and was due to depart for Fiordland at 6pm the same day.

The ship and crew of 1200 plus up to 3000 passengers are to remain at Port Chalmers until authorities clear the ship for departure.

Two Transport Accident Investigation Commission investigators board the ship this morning, but Roger Foley at the commission doesn't know how long the investigation will take.

'The investigation team is on site at the moment,” says Roger. 'There's some suggestion it may have to move from its current berth to make way for another one. If it does move it might go out to the stream at anchor.

'Sometimes investigators stay on board until the next port, but going to Fiordland and Australia wouldn't be a good look.”

The Emerald Princess departed Tauranga for Napier last weekend. She is expected to return on her next cruise on February 23.

Paramedics were called to the ship about 5.20pm on Thursday by the Fire Service. The man was dead at the scene.

In a statement, Carnival Australia communications manager David Jones says initial reports suggest the incident happened during technical work on the hydraulic launching system on a tender vessel.

"We are deeply saddened that a member of Emerald Princess' crew was fatally injured in the incident," says the statement.

TVNZ is reporting the explosion is thought to have been caused by a nitrogen gas cylinder. Nitrogen gas is not flammable.

Port Chalmers residents are reported saying the explosion was loud and sounded like container falling off a truck.

Click here for a view from the Emerald Princess' bridge cam