A collection of valuable private manuscripts by Franz Kafka is to be opened for the first time as part of a legal battle over his estate.

The four boxes, believed to contain unpublished writing and sketches by the Prague-born Jewish author, will be unlocked in Zurich to help lawyers determine where ownership lies.

Literary experts will study the documents, hidden for 50 years in the vaults of a Swiss bank and said to be worth hundreds of thousands of pounds.

It is just the latest stage in a two-year legal battle initiated by a woman called Eve Hoffe.

Her mother Esther was secretary to Max Brod, the man who published the novelist's work after his death from tuberculosis in 1924, despite having promised to destroy it.

Mr Brod left the original copies of the work to Esther Hoffe in his will. But during the Holocaust he fled to Tel Aviv, leading the state of Israel and the National Library in Jerusalem to claim rights over Kafka’s work.

The boxes in the Swiss vault are registered to Eve Hoffe and her sister, who argue that they are the rightful heirs to Mr Kafka’s estate.

Kafka who wrote the novel The Trial and the short story Metamorphosis among other works, is considered one of the most important writers of his generation.

A judge will decide whether the manuscripts should remain secret, or if they can be placed in a public archive or published.

Safe-deposit boxes in Tel Aviv vaults containing Kafka’s work were unlocked last week following orders from an Israeli court. However a legal ban, being challenged by the Ha'aretz newspaper, means the contents cannot be revealed.