For two years between 1963 and 1965, Singapore was part of Malaysia, and the regiment was renamed the Malaysian Infantry Regiment. Both battalions saw service in the Confrontation, with 1 SIR posted to Sebatik Island in Sabah and 2 SIR to Labis, Johor. On Singapore's independence in 1965, the regiment regained its former name. In 1967 two more battalions, the 3rd and 4th, were raised as part of the move towards National Service. 1 SIR and 2 SIR were also converted to NS battalions. Four further battalions were raised over the next few years, although 7 SIR and the older 8 SIR were eventually re-roled to become the 3rd and 2nd Battalions, Singapore Guards.