Norway's fisheries minister has resigned after taking his government-issued phone on an unapproved trip to Iran with his girlfriend.

Per Sandberg also quit as deputy leader the anti-immigration Progress Party, which governs in coalitions with the country's Conservatives.

Sandberg, 58, took a holiday to Iran with Bahaeh Letnes, 28, a former beauty queen who was born in the Islamic Republic but gained residency in Norway a decade ago and runs a fish export business.

He later admitted breaching protocol by taking his official mobile phone and failing to inform the prime minister of his destination and was rebuked by Prime Minister Erna Solberg.

The new fisheries minister will be Progress Party veteran Harald Tom Nesvik, the prime minister's office said.

Norway is the world's largest producer of farmed salmon, and seafood is the Nordic country's second-largest export industry after oil and gas.