Two paintings by Vincent Van Gogh were unveiled, barely damaged, at an Amsterdam museum on Tuesday, 14 years after they were stolen in a mafia heist.

The works, 1882's "View of the Sea at Scheveningen" and the 1884 "Congregation Leave the Reformed Church in Nuenen", are from a period that was crucial to the post-impressionist master's development as a painter.

"They are back," said Van Gogh museum director Axel Rueger ahead of the unveiling of the paintings, each valued by investigators on their recovery by Italian police six months ago at 50 million euros ($53.97 million).

"I never thought I'd be able to say these words."

The works were discovered deep in the heart of Italy last September behind a false wall in a villa that prosecutors said belonged to Raffaele Imperiale, who is accused of running an international cocaine trafficking ring.

The sea view, showing a single wave-tossed ship just offshore under a brooding Dutch sky, is important to the museum as its only work from the painter's period in The Hague, where he studied.

The other canvas depicts the church in the southern province of Brabant where Van Gogh's father was minister. After his father died, Van Gogh added black-clad mourning figures to the painting in tribute.

"The children are safely returned now and they really are safe," said Rueger, after pulling back a screen to show the paintings encased behind a thick glass frame. "They will remain here for many generations to come."

Italian investigators believe Imperiale is living in Dubai and running a construction business there. The arrests of 11 members of his alleged ring last January, including one man who turned state's witness, led investigators to the paintings.

They vanished in 2002 after thieves climbed a ladder on to the museum roof and broke into the building in a heist that took only four minutes. They escaped by sliding down a rope.

The sea view suffered minor damage when it was ripped from its frame, losing a piece of backing paper from the bottom-left corner. It was a "miracle" the paintings suffered no further harm over the following 14 years, Rueger said.

Several major items were uncovered in last September's raid, including a private plane. One investigator noticed an unusual-looking wall, behind which the paintings were found wrapped in cloth.