Greek culture minister Pavlos Geroulanos has resigned following the theft of dozens of priceless ancient artefacts from a museum in Olympia, the ancient birthplace of the Olympic Games.

Two masked men broke into the museum, tied up an employee and stole 60-70 small clay and brass statues, along with a gold ring, local authorities said.

"There were two of them and they had a gun," Olympia mayor Thymios Kotzias told Flash Radio, adding that they had immobilised the guard when the shift changed in the monring after having previously disabled the museum's alarm.

Geroulanos resigned immediately after the incident, though it had yet to be accepted by Prime Minister Lucas Papademos.

Olympia, birthplace of the ancient Olympic Games, is visited by hundreds of thousands of visitors each year.

In January, a painting by Pablo Picasso and one by Piet Mondrian were stolen from the National Gallery in Athens.