The initial years were busy with the unit creating a structure and recruiting members suitable for commando training, while conducting sub-unit and unit training activities.
The initial years were busy with the unit creating a structure and recruiting members suitable for commando training, while conducting sub-unit and unit training activities. B Company was raised in 1997, followed by C Company in 1999, both of which took 24 months to reach full maturity.
A small team from 4 RAR (Cdo) deployed to East Timor as part of the International Force for East Timor (INTERFET) in September 1999 providing close personal protection for the media and also as interpreters in the initial months. In 2000, elements were involved in the evacuation of Australian nationals from the Solomon Islands in June. While later that year, 4 RAR (Cdo) assisted with counter-terrorism at the Sydney Olympic Games as part of Joint Task Force 114, with C Company on standby as a response force such as providing a cordon around an incident site in support of the SASR.
4 RAR (Cdo) deployed again to East Timor as a part of the United Nations Transitional Administration in East Timor (UNTAET) in 2001. When notified to replace 1 RAR in East Timor, 4 RAR had not long previously been raised as a commando battalion, developing special forces capabilities to supplement those of the SASR. With the commitment to East Timor continuing, however, 4 RAR was re-roled as a light infantry battalion for deployment to East Timor as AUSBATT IV.
This involved reorganising from the existing two commando-companies structure to a light infantry battalion with four companies and a growth in the unit from 220 to 670 personnel. This saw B and C Company remain commando-qualified. A Company was formed in June 2000 followed by D Company in November both filled with Regular infantry soldiers posted in to the unit. The battalion took official control over Area of Operations (AO) Matilda in the northern border region on 25 April under the command of Lieutenant Colonel Jeff Sengelman.