Defence minister Luke Pollard claimed the £6.3bn programme had “left its troubles behind”, as Ajax declared initial operating capability (IOC), which means it can deploy a squadron on operations.
The multi-million pound vehicles, made in Merthyr Tydfil by General Dynamics, were originally due to enter service in 2019.
“This weekend, a small number of soldiers reported symptoms of noise and vibration, having taken part in an exercise involving the Ajax armoured fighting vehicle,” an MoD spokesperson said.
Upon testing “around 30 personnel presented noise and vibration symptoms”.
A “small number of personnel” are still receiving expert medical care, it added, but the “vast majority” have been cleared for duty.
“Out of an abundance of caution, the minister for defence readiness and industry has asked the Army to pause all use of Ajax for training and exercising for two weeks, while a safety investigation is carried out into the events this weekend.
“A small amount of testing of the vehicle will continue, in order to ensure that any issues can to identified and resolved.”