"These are the aircraft which are particularly well equipped for surveillance and reconnaissance, and as the conflict has gone on and the targets have become harder to detect it is important to have this capability available," Foreign Office Minister Alistair Burt told Reuters on the sidelines of an international Libya contact group meeting in Istanbul.
"They have the capability to launch airstrikes," he said.
NATO Secretary-General Anders Fogh Rasmussen called on Thursday for members of the alliance to provide more aircraft to bomb Muammar Gaddafi's forces in order to protect Libyan civilians and enforce a no-fly zone.
Together with France, Britain has taken a lead role in the NATO mission.
In addition to the ageing Tornadoes, Britain has also assigned Typhoon multi-role warplanes to the NATO mission, and the aircraft are stationed at Gioia del Colle in south-west Italy, some 600 kilometres from the Libyan coastline.
"This latest deployment will bolster NATO's reconnaissance capability. The deployment will have no effect on operations in Afghanistan," Major General Nick Pope, the Chief of the Defence Staff's communications officer, said.
"As a formidable attack aircraft this deployment will also provide a useful secondary increase to NATO's overall strike capability."
Pope said a Typhoon launched a Paveway missile to destroy an armoured personnel carrier from Gaddafi's forces at Ziltan, west of the embattled rebel city of Misrata on Thursday.
"The RAF alone has to date damaged or destroyed more than 500 military targets including command and control sites," he said.
"But as the campaign has progressed, the regime is increasingly attempting to conceal troops, equipment and headquarters, often in populated areas."