A cruise ship turned up unexpectedly in Tauranga this morning.

Radiance of the Seas arrived just after 7am for a day visit, their first port of call since leaving Melbourne.

Port of Tauranga commercial manager Leonard Sampson confirms the vessel was not scheduled to be here.

'We understand they have altered their route from the South Island due to forecast bad weather, so now they're just doing North Island port calls. They contacted us and asked if they could come, and we said sure, we'd love to have you.”

A couple on board from Australia who had been planning to get married in Dunedin Botanical Garden decided to get hitched in Tauranga instead, after the bad weather scuppered their plans.

Kellie and Jade planned to visit the local registry office when they were told local cruise ship ambassador Jan Innes is a marriage celebrant.

Jan checked all the legal requirements and with two other ambassadors as witnesses she conducted the marriage ceremony in Coronation Park.

The ship is due to leave at 6.30pm, with Auckland (and hopefully some good weather) their next stop.