Air travellers to Greece and the Red Sea have been warned of the threat of flight disruption.
EasyJet said it had been advised of potential strike action by Greek unions on Wednesday. "We expect significant disruption," the airline said.
The carrier also said there is a possibility of some disruption out of Sharm el-Sheikh today and tomorrow due to the eruption of Volcano Nabro in the north east African nation of Eritrea late on Sunday following a series of earthquakes.
The ash cloud is heading towards Israel where authorities said it was still too early to say whethe it would cause disruption to flights.
Haaretz.com reported officials from the Civial Aviation Authority and the meteorogical service would meet later today to "discuss possible scenarios".
The ash cloud has caused the airport at Addis Ababa to close and US secretary of state Hilary Clinton to cut short a visit to the country as the cloud spread over parts of east Africa.
The problems come on top of the eruption of Chilean volcano Puyehue, which continues to disrupt flights as far south as Australia.