The prime minister has restated that British troops will not go onto the ground in Mali, despite the UK offering logistical support to France.
The first of two RAF C17 cargo planes sent to help French military efforts against Islamist rebels is delayed in Paris due to technical issues.
David Cameron said: "What is being done in Mali is in our interests and should support France's actions."
France has attacked the militants since Friday, to support Mali's government.
Its armed forces have been helping government forces in the West African country recapture the central town of Konna.
France has called a meeting of the UN Security Council to discuss the situation in Mali on Monday.
The first of the two C17s left RAF Brize Norton in Oxfordshire on Sunday and was loaded with French armoured vehicles and other equipment at the Evreux airbase in Normandy overnight.
It was due to fly to Mali's capital, Bamako, on Monday morning, but has been delayed due to a "minor technical fault", a Ministry of Defence spokesman said.
The problem is thought to be a short-term one and the plane is expected to be ready to depart later.
A second C17 is due to leave the UK on Monday morning.
The UK prime minister and French President Francois Hollande spoke on Saturday and agreed that the situation in Mali posed a real threat to international security due to terrorist activity there.
Mr Cameron told BBC Radio 4's Today programme Britain would also share intelligence with France as part of its campaign.
"There is a very dangerous Islamist regime allied to al-Qaeda in control of the north of that country. It was threatening the south of that country and we should support the action that the French have taken," he said.
"So we were first out of the blocks, as it were, to say to the French 'we'll help you, we'll work with you and we'll share what intelligence we have with you and try to help you with what you are doing'."
The Minister for Africa, Mark Simmonds, has indicated British personnel could play a role in training the Malian army through a European Union initiative.
A government statement on Mali is expected in the Commons at 15.30 GMT.
The government's National Security Council (NSC) is set to discuss the situation in Mali when it meets on Tuesday.
Meanwhile, the French Foreign Minister Laurent Fabius has said that France's involvement in the campaign in Mali will last "a matter of weeks".
He said if France had not intervened, there was a risk that Islamists could have advanced as far as the capital, Bamako, with "appalling consequences".
On Sunday, French warplanes bombed the town of Gao in eastern Mali, extending their raids deep into rebel territory.
The French intervention had succeeded in stopping their advance towards the south, he added.
Islamist groups and secular Tuareg rebels took advantage of chaos following a military coup to seize northern Mali in April 2012.
But the Islamists soon took control of the region's major towns, sidelining the Tuaregs.
One Islamist group, Ansar Dine, began pushing further south last week, seizing the strategically important town of Konna.
The town has since been recaptured by Malian troops with French aerial support.
France's decision to intervene in its former colony took many by surprise.
A UN-backed international force from countries in Ecowas, the West African regional bloc, had not been expected until the autumn.