Ministers have assured British troops will not be drawn combat operations against al Qaida-backed rebels in Mali ahead of a meeting of the National Security Council on Tuesday.
Ministers insist the UK is providing only "limited logistical support" in support of the French military mission in the west African state, with no plans to deploy ground forces.
The first of two giant RAF C-17 transport aircraft was due to leave Paris last night with supplies for the French force sent in by President Francois Hollande following an appeal for help by the Mali government.
Britain is supplying logistical support and two C-17 transport aircraft
A second C-17 is expected to leave today after encountering what was described as a "minor technical fault" in the French capital.
Foreign Office minister Mark Simmonds said a "small detachment of technical personnel" was already at the airport in the capital Bamako to "operate and if necessary defend" the aircraft.
In a Commons statement yesterday he said David Cameron had made clear Britain was offering only limited back-up support when he spoke to Hollande at the weekend.
"The Prime Minister has made categorically clear that the initial supporting deployment will be for a period of one week," he said.
"He has also made clear that there will be no combat troops from the UK involved and we have no plans to provide more military assistance."
He said the situation in Mali was of "grave concern" to the UK and that it was essential to prevent the rebel-held north becoming a "springboard for extremism" in the region.
Meanwhile the European Union has said it is bringing forward a planned military training mission to Mali, which will now be launched "in the second half of February or early March".
Hundreds of French troops were deployed to the country on Saturday after the rebels overran the strategically important town of Konna last week.
Despite the presence of the French, the government forces suffered a further setback with the loss of the garrison village of Diabaly in central Mali, taking the rebels within 250 miles of Bamako.
Former foreign office minister Peter Hain expressed scepticism at predictions by the French that their troops would be out of the country "in a matter of weeks".
"That seems to me pretty unlikely," he said. "This could become an incredibly long, drawn-out and difficult morass."
A Ministry of Defence spokeswoman said an RAF C-17 carrying French military personnel and supplies has now arrived in Bamako.