PARIS: French civil servants went on strike Thursday for better pay in their first mass show of dissent since the Socialist Francois Hollande became president last year.

Dozens of street protests were planned across the country as part of the day of action called by three of the several unions which represent France's 5.2 million state workers.

The main complaint of the unions relates to the index used to calculate salaries, which has been frozen for three years.

Raising the index by one point would cost 800 million euros ($1 billion) if applied only to central government workers or 1.8 billion euros if applied to all civil servants, according to the state audit authority.

Jean-Marc Canon of the CGT union said the situation was "absolutely catastrophic", and noted that nearly a million civil servants were were being paid the minimum wage.

The unions are seeking to put pressure on Civil Service Minister Marylise Lebranchu ahead of pay talks next Thursday.

She has acknowledged "the difficult situation facing civil servants" but hinted that pay rises were unlikely given the budgetary constraints on the government.

The government was due later Thursday to announce how many civil servants had answered the strike call.