Raffarin's sacking was seen as a virtual certainty by some

However, the entire French government has also formally resigned, and some other key figures may be replaced.

President Jacques Chirac's centre-right UMP party was virtually wiped off the regional political map, sparking wide predictions of Mr Raffarin's sacking.

But on Tuesday the presidential palace announced he was staying in his post.

Jacques Chirac has just given the French people the two fingers (insult) Jean-Marc Ayrault Socialist leader in parliament

The new line-up would be announced on Wednesday and the incoming cabinet would hold its first meeting on Friday, officials said.

Mr Chirac, meanwhile, delayed a visit to Moscow which he had been due to undertake later this week.

Mr Raffarin, who has been implementing Mr Chirac's unpopular social reform programme, could still leave office later in the year, correspondents predict.

But the socialists quickly accused the president of ignoring the message he had received from voters at the weekend.

Analysis: Chirac's tactics Are reforms doomed?

"Jacques Chirac has just given the French people the two fingers (insult)," Jean-Marc Ayrault, head of the Socialists in parliament, said in a statement.

Pensions and employment laws are among the areas being tackled in the government's unpopular reform programme, but the public has not been won over.

Voters across France switched to the socialists in Sunday's second-round vote, in what was widely interpreted as a protest vote against the reforms, high unemployment and a stagnant economy.

Of the 21 mainland regions, only Alsace stayed under the UMP's control.

If Chirac wants to continue with the reforms, it is better that they be done by Raffarin, who is already worn out and very unpopular. Nothing worse can happen to him Paul Bacot Political analyst

The socialists held their existing eight regions, and seized another 12 from the centre-right.

Analysts said Mr Chirac was probably biding his time, keeping his unpopular PM until the reforms had progressed further.

"If you want to go down a road full of potholes, you are better go down it with a battered car than with a new one," said political analyst Paul Bacot.

"If Chirac wants to continue with the reforms, it is better that they be done by Raffarin, who is already worn out and very unpopular. Nothing worse can happen to him.

"The problem the president probably has is that European elections are near. It would be difficult to turn the situation around and improve the government's image in so short a time.

"He would have wasted a new prime minister due to the risk of the European elections mirroring the regional ones."