The Regiment saw ferocious fighting during the Japanese invasion of Malaya; the 2nd Battalion, part of the 28th Brigade, saw heavy fighting at Jitra where it was forced to hastily retreat after taking part in the initial resistance on the Asun and being isolated and confronted by overwhelming Japanese forces which included tanks. The 2nd Battalion was in action a few weeks later at Kampar where they successfully held off superior forces. Within a few days they were again in action but were out-numbered and sustained heavy casualties during the engagement at the Slim River Bridge on 7 January. The Allies had withdrawn from Malaya, to Singapore, by January 1942. The Japanese subsequently launched an invasion of Singapore and bitter fighting ensued; Singapore, which had once been perceived as impregnable, fell on 15 February 1942 with 130,000 British, Australian and Empire troops, including men of the 2nd Battalion, taken prisoner by the Japanese.