Britain intends to resume the delivery of non-lethal aid to rebels in Syria after it was suspended in December following advances by Islamist groups, Foreign Secretary William Hague has announced.

The United Kingdom will send £1mn ($1.6mn) worth of communications equipment, vehicles, generators and medical kits to the Free Syrian Army (FSA) "as soon as is practical," he said.

"I am now lifting the hold on those plans to deliver equipment to the Supreme Military Council of the Free Syrian Army in Syria," Hague said in a written statement to parliament on Thursday.

"Both the UK government and the Supreme Military Council are confident that the equipment can be delivered safely."

Britain and the United States suspended their aid after the the FSA, considered a "moderate" rebel group, lost control of arms depots and the key Bab al-Hawa crossing on the Turkish border to a powerful alliance called the Islamic Front.

It was a major blow to the FSA, which was once the country's strongest armed opposition force but is now increasingly marginalised by other militants fighting in the civil war, including the Islamic State of Iraq and the Levant (ISIL).

"This resumption of delivery clearly demonstrates our continued and longstanding support for the National Coalition and the Supreme Military Council of the Free Syrian Army, who represent the majority of Syrians who support a political settlement and a democratic, pluralist future for their country," Hague added.

The aid consists of laptops with satellite Internet connections, mobile telephones and radios; pick-up trucks, portable generators and fuel; and clothing, rations, tents and individual medical kits.

It is the second delivery from Britain to the Supreme Military Council. The first, in August 2013, included equipment to protect them from chemical weapons attacks.

Last week, the UK calculated that it has to date pledged £600m to humanitarian aid for Syrians affected by the conflict, with £59m of that yet to be allocated to specific projects.