President Francois Hollande said on Thursday that French troops would not interfere in the internal affairs of its former colony the Central African Republic, where rebels have seized a large chunk of territory in recent weeks.

"If we are present, it is not to protect a regime, it is to protect our nationals and our interests, and in no way to intervene in the internal affairs of a country, in this case Central Africa," he said. "Those days are gone."

His comments came a day after hundreds of protestors demonstrated in front of the French embassy in Bangui, angry over what they say is Paris's inaction in the face of the rebel advance.

France has around 250 soldiers based at Bangui airport providing technical support to a peacekeeping mission run by the central African bloc ECCAS, according to the defence ministry in Paris.

The ministry said Wednesday that the troops would help ensure the safety of the 1,200 or so French citizens in the country and assist in the reconstruction of the Central African armed forces.

Asked whether France would intervene to help displaced people or refugees Hollande said that France could only step in "if there is a UN mandate", adding that "this is not the case".

"Generally speaking, we are always in favour of civilians being protected and we will do what is our duty," he said.

Hundreds of demonstrators close to embattled President Francois Bozize had on Wednesday turned on the embassy, protesting France's failure to help push back the rebels sweeping across the resource-rich but poverty-stricken nation.

With the government now largely restricted to Bangui, Chadian troops sent last week to help the increasingly fragile regime are the only real obstacle to rebel forces now sitting about 300 kilometres (200 miles) away.