A vast steel roof above the Akrotiri archaeological site on the Greek island of Santorini collapsed yesterday, killing one visitor and injuring at least six others, officials said.

The steel structure above the ancient Minoan city of Akrotiri gave in after it was covered with soil to blend in with the Aegean island's environment.

"The workers were watering the soil on the roof when it collapsed," a police official told Reuters.

He said two American, two Slovak and a German tourist as well as a Greek worker were injured.

The nationality of the person who died and was still trapped under the roof was not yet known.

The official said the contractor and the architect of the 1,000 sq meter roof had been arrested and would appear before a prosecutor.

Special rescue teams from Athens were flown in to assist in lifting the roof.

Deputy Culture Minister Petros Tatoulis, whose ministry funded the project, was also on his way to examine the details of the accident, his office said.

The roof protecting the ancient Minoan city at the southern tip of the volcanic island was installed five years ago to reduce weather damage and to allow further excavations.

"We heard a loud noise as if a building was collapsing, we don't know how it happened," an employee at the site told Reuters.

"A very large part of the roof has collapsed and it must be visitors trapped underneath because all employees are accounted for," she said.

One of the most popular archaeological sites in Greece, the spectacular Akrotiri ancient city was discovered in 1967 by Greek archaeology professor Spyridon Marinatos. He died on the site in 1974 when he fell while inspecting excavation work.