Greek authorities are warning of possible power cuts at the heart of the summer tourist season as electric utility workers head for protracted strikes against government plans to break off and sell part of the country's dominant power producer.

Public Power Corporation unions have vowed to launch rolling 48-hour walkouts Thursday, arguing that electricity supply is a vital commodity that should stay under state control.

The conservative-led government insists it will carry out the sale — which was demanded by the recession-plagued country's international creditors. It is threatening to force strikers back to work with a mobilization order.

Prime Minister Antonis Samaras said Wednesday he would not bow to "fanatic populists."

Since 2010, Greece has survived on international bailouts granted on condition that it implements tough austerity measures,