The British government said on Tuesday it was making up to 5,300 army personnel redundant as part of cuts that will see troop numbers reduced to the lowest since the early 19th century.

The Ministry of Defence said soldiers returning from or heading to Afghanistan would be exempt from the cuts, the third such round under a programme that will see the army reduced from 102,000 regular troops to 82,000 by 2020.

"Whilst we need to make up to 5,300 army personnel redundant, the programme will not adversely affect operations in Afghanistan," junior defence minister Mark Francois insisted in a statement to parliament.

Britain still has about 9,000 troops in Afghanistan ahead of a scheduled withdrawal in 2014.

The Conservative-led coalition government of Prime Minister David Cameron, which is trying to shrink Britain's massive deficit, has already announced that reservist numbers will be doubled to 30,000 by 2018 to help fill the shortfall.

But the opposition Labour party has questioned the fresh defence cuts in the wake of the hostage crisis at a Algerian gas plant, where at least 37 foreigners were killed, and the French-led assault against Islamist rebels in Mali.

Labour's defence spokesman Jim Murphy accused the government of implementing a "carry on regardless" strategy by announcing thousands of redundancies a day after Cameron vowed to show "iron resolve" in fighting Islamist terrorism.

"The threats have increased and yet the army has been cut to just 82,000," Murphy told parliament.

"There will be a growing sense in the country that ministers are unprepared for events in North Africa and beyond."

Francois insisted that reservists would be able to fill the gap. "We are reconfiguring our armed forces," he told MPs.

"While we are reducing the number of regulars over time we are increasing the number of reservists and I believe we can achieve that balance in good time."

Britain's navy and air force are also shedding 5,000 posts each under the Strategic Defence and Security Review announced in 2010, while the Ministry of Defence is losing 25,000 civilian jobs.

Francois warned that further army redundancies were "likely" along with job cuts among the medical and dental personnel working with the navy and air force.

Cameron acknowledged on Monday that, "of course, there are always challenges about the level of resources -- even in times when money is plentiful, and it isn't plentiful today."

But he added: "If you look at the defence and security budget, it is actually in cash terms stable at 33 billion Pounds ($52 billion, 39 billion euros).

"What we have tried to do as a government, and perhaps we need to look again and go even further, is to focus on those threats to our security we face today."