Greek authorities declared Tuesday an emergency on the island of Chios after heavy rainfall caused widespread flooding and killed a man trapped in his car.

"The situation was unprecedented for our area, having so much rainfall in a short space of time," the prefect of the eastern Aegean island, Polydoros Lambrinoudis, told state television NET.

An elderly man was found dead in his car after being trapped in a torrent and the local fire department received hundreds of emergency calls from residents whose homes, basements and shops had flooded.

"Until this morning we had received 310 emergency calls," local fire chief Iakovos Archontakis told the channel.

"Ten of them were from people trapped in their cars who were in immediate danger."

Flooding was also reported on the neighbouring island of Ikaria where rescue crews helped six people immobilised in their vehicles. Two people were injured, according to the semi-state Athens News Agency.

Greece has experienced an unstable storm front with sudden weather swings since the weekend.

At the other end of the country, a whirlwind struck the Ionian island of Zakynthos and toppled trees, ANA said.