Ten years after one of Europe's worst oil disasters, the captain of the Prestige tanker blamed Spain for sending his vessel away from the coast and into the stormy Atlantic.

Facing trial a decade to the day after his tanker sent an SOS that heralded the biggest oil spill in Spanish history, the 77-year-old Greek skipper criticised the decisions taken by the Spanish authorities.

"The ship was cracked and they sent it out to the ocean," said the captain, Apostolos Mangouras.

"It was the worst alternative. They sent us in a floating coffin... to drown."

Mangouras said that on November 15, two days after sending a distress signal, the Prestige was expecting a storm. "Where were we going? Eight souls were aboard," he told the prosecutor.

The captain said he did not specifically ask to go into port because he believed the tanker was being sent to shelter.

But after passing the Galician peninsula of Cape Finisterre, he said, "I realised that they were sending the boat out to the ocean."

Mangouras said he had visually checked the hull and ballast tanks before departing Saint Petersburg two months beforehand. He and the Philippine crew held all the required qualifications, he said.

The ill-fated tanker's skipper was the first of four accused to testify in the trial over the catastrophe in which tens of thousands of tonnes of thick, sticky oil oozed across the coasts of Spain, Portugal and France.

Prosecutors have charged the captain with criminal damage of the environment and a protected nature reserve and are seeking a combined jail term of 12 years.

They are also demanding more than four billion euros ($5.0 billion) in damages.

Outside the exhibition centre where the trial is being held in the northern port city of A Coruna, Greenpeace activists hung a huge yellow banner asking "Where are the guilty?" along with photographs of various politicians.

Among the photographs was one of right-leaning Prime Minister Mariano Rajoy, who at the time was deputy premier and initially downplayed the gravity of the accident, repeatedly describing the black spots that appeared in the sea where the tanker went down as "small threads of clay".

The Prestige, a Bahama-flagged Liberian tanker, was carrying 77,000 tonnes of fuel when it sent a distress call in the midst of a storm off the northwestern Spanish coast on November 13, 2002.

The conservative Popular Party government in power at the time ordered the Prestige out to sea away from the Spanish coast instead of following an emergency contingency plan prepared by experts that called for it to be brought to port where the leaking oil could be confined.

For six days the tanker drifted in the Atlantic, its hull torn by a leak, before breaking up and foundering 250 kilometres (155 miles) off the coast into waters some 4,000 metres (13,000 feet) deep, spilling some 50,000 tonnes of oil into the ocean and coastline.

Over the weeks that followed 300,000 volunteers from Spain and the rest of Europe joined local people in scraping the oil from the blackened rocks and beaches, armed with little more than buckets and their bare hands.

Others charged are Greek chief engineer Nikolaos Argyropoulos and first mate Irineo Maloto, a Filipino whose whereabouts are unknown, and Jose Luis Lopez-Sors, head of the Spanish merchant navy at the time, who ordered the ship out to sea when it was losing fuel.

Greenpeace warned that a similar accident was still possible.

"Nothing has changed, not the government, not the legislation, not our dependance on oil," said Greenpeace Spain director Mario Rodriguez.

The trial is due to last until May and hear testimony from 133 witnesses and 100 experts.