The crews are being sent to Helmand Province in southern Afghanistan to fly British troops, the Ministry of Defence confirmed yesterday.
Helicopters have become the preferred mode of transporting troops because there is less risk of roadside bombs.
Many of Britain's 114 deaths in Afghanistan have been caused by mines, IEDs (Improvised Explosive Devices) and suicide bombs directed at troops travelling by land.
It is also hoped the extra support will prevent pilots being run into the ground.
But the move will see the number of crews available at each of Britain's six RAF search and rescue stations reduced from five to four.
And it is feared the current ability to respond to emergencies within 15 minutes will be put at risk.
The teams respond to more than a thousand call-outs a year.
Incidents vary from stranded hill walkers to devastating floods, such as those in Boscastle, Cornwall, in 2004.
The crews work alongside four civilian coastguard and two Royal Navy teams, ensuring nowhere in the UK is more than an hour's flight away, or an hour and a half at night.
An MoD spokesman said: "The RAF search and rescue teams are the most dedicated and professional in the world.
"They provide at least one committed standby helicopter at six bases throughout the United Kingdom able to respond within 15 minutes.
"Changes have been made to crew structures at these bases in order to provide additional support to our top priority, operations in Iraq and Afghanistan.
"This will not affect normal search and rescue capability and our support to civil authorities during recent flooding shows our ability to respond flexibly to extraordinary requirements."
He added: "Operations are always our priority. We have to focus our resources on the front line."
On Thursday Defence Secretary Des Browne held a meeting with senior military personnel and civil servants to consider how to tackle Britain's helicopter shortage.
One option is for Britain to rent helicopters from other countries or commercial companies in order to make up for a shortfall in Afghanistan and Iraq.
British forces in Helmand province in southern Afghanistan can draw on eight Chinook helicopters capable of carrying up to 40 passengers, four Royal Navy Sea Kings and four Army Air Corps Lynxes. There are also eight Apache helicopter gunships, which carry no passengers.
The Ministry of Defence said its aim was to ensure a future helicopter fleet that has the right mix of numbers, capability and platform types, to support current operations and future requirements.
Extensive modifications have been carried out to improve the capability of helicopters operating in Afghanistan, including the fitting of new rotor blades to Sea Kings to improve performance in hot conditions and higher altitudes.
Commanders in Afghanistan are also being offered more hours flying time each month from the Chinook and Apache fleets.
Over the next 10 years, the MoD plans to spend £6 billion to replace and enhance helicopter capability through its Future Rotorcraft programme.
