Norway's justice minister has submitted his resignation after his partner was accused of setting his car on fire and other threatening acts.

Justice Minister Tor Mikkel Wara said during a news conference on Thursday: "There is someone who needs me more than the government does...my family."

Earlier in the day, Norway's domestic security agency said the minister's partner, Laila Bertheussen, was detained for questioning in eight crimes targeting Wara since December.

The agency, known as PST, said they include the car arson, sending an anonymous threatening letter to Wara, setting the garbage container outside Wara's home on fire and scrawling graffiti on the house.

Bertheussen denies wrongdoing.

Wara joined Norway's center-right government last year. He said he is stepping down Friday.