Israeli authorities said Sunday they had cleared a Greek tanker of suspicion in relation to an oil spill that caused massive tar pollution on the Mediterranean coastline, devastating marine life.

It is seen as Israel's worst maritime pollution incident in decades.

Powerful winds and unusually high waves pummelled Israel's entire Mediterranean coastline on February 17, with tonnes of tar staining 160 kilometres (96 miles) of beach from its borders with the Gaza Strip to Lebanon.

Volunteers have teamed up with authorities to clean the beaches, while officials from the environmental protection ministry launched an investigation into the source of the spill.

After an Israeli media report had named the Greek oil tanker Minerva Helen as a possible culprit, the ship's owner, Minerva Marine Inc., firmly denied any involvement. 

On Sunday, the ministry said that "following an inspection conducted in Greece on the Minerva Helen tanker, it has been cleared of suspicion of involvement in the severe tar event on Israel's beaches".

The ship's owner said the Israeli media report was an "unfounded an inaccurate allegation".

It stated that the ship had been in the Mediterranean in the days before the storm, "without any cargo on board" and therefore could not be linked to a spill. 

The company also pledged to "cooperate with any relevant authority" interested in the Minerva Helen's movements. 

On Saturday in the Greek port city of Piraeus, Israeli inspectors conducted "an extensive examination" of the Minerva Helen that "positively ruled out the vessel as the source of the pollution," the environmental protection ministry said in a statement.

The investigation was conducted in coordination with Greek authorities, with assistance from the Hellenic Coast Guard, the ministry said.

"We're committed to take all the efforts to locate the ship behind the pollution on Israel's coast," Environmental Protection Minister Gila Gamliel said in a statement.

"This pollution has a source, and we won't accept an environmental felony," she said.

According to the ministry, there were currently "dozens" of vessels under suspicion, with Israeli inspectors, aided in some cases by international bodies, already ruling out around 10 of them.