Britain's junior defence minister Mark Lancaster said in a statement to parliament that the previous five-year residency requirement for Commonwealth army recruits has been removed.

"Applications will be accepted from all Commonwealth countries," Lancaster said in his statement, adding that the reform had been introduced "in light of changes to the size of our armed forces".

Lancaster said that Commonwealth applicants would have to be aged over 18 -- two years more than the minimum for Britons -- so as "to mitigate the risks associated with unaccompanied minors travelling to the UK without the guarantee of a job".

A limited waiver to the residency requirement had already been introduced in 2016 to allow up to 200 Commonwealth personnel per year to fill skill shortage posts. This cap has now been increased to 1,350 across navy, army and air force personnel.

The Commonwealth is an association of 53 states, most of them former British colonies, including Australia, Canada and India.

Lancaster also said that a 15-percent limit on Commonwealth nationals in strategic British army positions would be maintained "to sustain operational effectiveness".

A report by the National Audit Office, an independent government watchdog, earlier this year found that the full-time military was running a 5.7 percent shortfall in its ranks.

An extra 10,600 recruits were required to fill the "largest gap in a decade," the report said.