German police on Tuesday handed over to Israel thousands of stolen papers and manuscripts belonging to Max Brod, the friend and literary executor of Czech writer Franz Kafka.

Brod, who died in Tel Aviv in 1968, is primarily responsible for Kafka's success as one of the 20th century's most influential writers, having published many of his works after the writer's death in 1924.

Prague-born Brod had fled from Adolf Hitler's Nazi regime to Tel Aviv in 1939, carrying Kafka's estate in his suitcase, even though the writer of The Trial had insisted his works be destroyed after his death.

A ceremony in Berlin at the residence of Israeli Ambassador Jeremy Issacharoff on Tuesday saw German police hand thousands of Brod's personal papers over to the National Library of Israel.

It ended a decade-long struggle to retrieve the missing Brod papers which, according to Israel's National Library, were stolen 10 years ago in Tel Aviv.

The documents, letters and memoirs re-emerged in 2013, when two Israelis approached the German Literary Archives in Marbach, and private collectors, with a huge collection of unpublished documents belonging to Brod.

The significance of the papers, including a postcard from Kafka sent to Brod in 1910, quickly emerged and they were confiscated after an attempted sale.

"The authorities were notified and it became clear that the some 5,000 pages of documents were part of Brod's private archive and had been stolen," the Israeli Embassy in Berlin said in a statement.

In January 2018, a court in Wiesbaden ruled that the papers should be handed back to Israel's national library.

"The correspondence found in the archive is extensive and impressive," said Stefan Litt, the library's archivist and humanities collection curator.

"It can be characterized as a type of 'who's who' of the European cultural world in the first four decades of the 20th century."

The manuscripts, including unpublished passages from Brod's diary and early correspondence with his wife, could provide further insight into the life of Kafka, whose best-known works also include The Castle.

When Brod died in 1968, he left his personal papers and Kafka's manuscripts to his secretary Esther Hoffe.

After her death in 2007, aged 101, the papers wenat to her daughter Eva, from whom part of the collection was stolen.

Over time, the collection was split into three locations: an Israeli bank vault, a Swiss bank safe in Zurich and Eva Hoffe's flat in Tel Aviv.

Courts in Israel, Germany and Switzerland have determined the archive should be safeguarded at Jerusalem's National Library where, in accordance with Brod's wishes, it can be preserved and made available to the public.