PARIS - President Nicolas Sarkozy reappointed his trusted ally Francois Fillon as France's prime minister on Sunday, seeking to shore up his position 18 months before the next parliamentary election.

"The president has asked the prime minister to put forward a new government," a statement from Sarkozy's office said. Fillon submitted his government's resignation late on Saturday before a long-awaited ministerial reshuffle.

Fillon said in a separate statement he planned to enter a new period of government with determination, on the back of the reforms carried out since he first became prime minister at the start of Sarkozy's term in 2007.

"After three-and-a-half years of brave reforms, carried out despite a severe global economic and financial crisis, I am starting ... a new phase with determination which will allow our country to strengthen the growth of the economy to help jobs, promote solidarity and safeguard the security of all French people," he said.

Sarkozy had been widely expected to reappoint Fillon and to avoid any surprises in his cabinet reshuffle.

An official at the prime minister's office said the line-up of the new government would be announced on Sunday or Monday.

Fillon has devoted his career to politics, holding various government posts including labour, social affairs, education, and post and telecommunications ministries.

He made his debut in centre-right administrations in 1993 as minister for higher education and research.

As labour minister in 2003, he shepherded an important change to France's pension system through parliament, despite union protests, obliging civil servants to contribute for the same length of time as private sector employees to qualify for a pension.