The recent discovery of the remains of a shipwrecked 4th century BC vessel, nicknamed Kythnos I after the Greek island near which it was found, is the latest testimony of the archaeological riches still submerged in Greek waters.

It also demonstrates the technological advances that underwater archaeology has made in this country in recent years.

Greece has no shortage of skilled archaeologists. But when it comes to underwater research, it is only recently that the Greek ministry of culture has begun mixing academic knowledge with hi-tech wizardry.

Collaboration with the national centre for maritime research (Elkethe), and increased state funding from 2000 onwards, have enabled the culture ministry to open a broad - and still potentially untapped - archaeology frontier under the waves.

Elkethe, which operates under the development ministry, has given the culture ministry access to its specialised resources, including a 42m oceanography boat (the Aigaio), a submersible (the Thetis), two remotely-guided craft and a team of expert divers.

"This collaboration has spurred on efforts to chart underwater archaeological treasures, as did three laws on protecting such finds and preventing their pillage," ministry director of underwater antiquities Katerina Dellaporta said.

Pooling their resources, the ministry and the research centre have located more than 30 shipwrecks from Classical, Hellenistic, Roman and Byzantine times, at depths that can reach 550m.

Ministry archaeologists have so far recovered objects from only a few of these wrecks.

In March 2004, two groups of amphorae were discovered at a depth of 45m off the coast of Samos, in the eastern Aegean Sea. They came from a ship believed to have sunk between the 3rd and 2nd centuries BC.

Two days later, at a short distance to the north, the sonar picked up another pile of amphorae at a depth of 67m off the coast of Chios. The second group of storage vessels dated from between the 5th and 4th centuries BC.

In September 2004, the discovery of an ancient bronze statue in a trawler net off the island of Kythnos in the western Aegean led ministry experts to examine the area more closely.

A few months later, armed with a geophysical study carried out by a 16-strong team of experts in March, the crew of the Thetis submersible found a concentration of amphorae at a depth of 495m belonging to the ship, subsequently named Kythnos I.

Despite intensive fishing in the area, the amphorae were preserved in seabed mud and remained in good condition.

This summer, the ministry team will relocate to the waters off Evia island, in the eastern Aegean, in a bid to pinpoint the remains of the Persian fleet of King Darius, wrecked by a storm in the 5th century BC during a seaborne invasion of Greece.

The search will be carried out with the assistance of the Canadian Archaeological Institute of Athens.

Another group of researchers, the Hellenic Institute of Marine Archaeology (IENAE), has been providing expertise in underwater archaeology for the past 30 years thanks to both state and private funds.

The institute was founded in 1973, at a time when Greece had no equivalent state authority in the field. In 1975, the centre joined the team of renowned French explorer Jacques-Yves Cousteau for a search of Greek waters. The culture ministry's own underwater antiquity department was only formed a year later. IENAE's most important discoveries to date include two shipwrecks from the 23rd and 13th centuries BC, found in the 1990s in the Gulf of Argolid, in the northeastern Peloponnese.