The Crown Princess met with Epstein, who committed suicide in prison this year following his arrest in the US on federal charges for sex trafficking minors.
The meetings took place after Epstein was convicted for sex offences in 2008, newspaper Dagens Næringsliv (DN) reports.
On Monday, the Crown Princess issued an apology for having met Epstein.
“I never would have associated with Mr. Epstein if I had been aware of the seriousness of the crimes he committed. I should have investigated his past more thoroughly, and I am sorry that I didn't,” read the statement, which was sent to DN by the Norwegian palace.
Crown Princess Mette-Marit met Epstein several times between 2011 and 2013, introduced by mutual acquaintances, according to the report.
The millionaire financier in 2008 admitted and was convicted of procuring an under-age girl for prostitution. He served 13 months in prison.