A Somali pirate has said he will free a kidnapped Danish family and drop demands for a US$5-million ransom if he can marry the 13-year-old daughter of his captives.

The proposal piles the pressure on the Danish government and various negotiators to secure a quick release of the five-member Quist Johansen family, who were on a two-year round-the-world sailing trip when they were kidnapped about 500 kilometres off the Somali coast a month ago.

The family is being held on a hijacked Greek freighter, MS Dover, with 20 other hostages.