Israel confirmed on Tuesday that the victim of a plane crash in Greece was a witness in a trial involving former prime minister Benjamin Netanyahu, as Greek officials launched an inquiry.

Senior Greek air safety official Ioannis Kondylis said a fisherman who witnessed the incident near Samos island on Monday claimed he had heard two explosions, though the cause of the crash is not yet known.

The Israeli foreign ministry identified the victims of the Cessna C182 single-engine plane crash as Haim and Esther Giron, a 69-year-old Israeli couple from Tel Aviv.

Haim Giron, the former deputy director at the communications ministry, was scheduled to testify at a trial involving Netanyahu, the Israeli prosecutor's office told AFP.

Among several charges, Netanyahu is accused of giving regulatory favours to media moguls in exchange for favourable coverage.

Giron had been expected to testify on allegations that the former PM negotiated with a telecommunications firm to secure positive coverage in exchange for policies benefitting the company.

The Greek civil aviation agency said the four-seater plane had taken off from Haifa on a private flight, and disappeared from radar shortly before its scheduled landing at Samos island airport.

Kondylis, head of the state air accident investigation and aviation safety board, on Tuesday said a team of specialists would fly to Samos on Wednesday to inspect the wreckage.

"A fisherman said... there was a large explosion, followed by a smaller one," Kondylis told AFP.

"The wreckage will show if that's the case," Kondylis said, adding that the wreckage was around 33 metres (108 feet) underwater.

The wreckage location is two kilometres (1.2 miles) south of the airport, Kondylis said.

He added that he was "hopeful" there would be more clarity on the causes of the crash over the next two weeks.