The ship was assigned the pennant number L134 during 1973. At the start of the year, "Sydney" was marked for a potential deployment to Mururoa in support of a Royal New Zealand Navy frigate sent to protest French nuclear testing at the atoll. The former carrier was chosen as she was capable of replenishing smaller vessels, and the RAN's dedicated replenishment oiler, , was undergoing refits. The Australian government did not want to send a warship until all other avenues of protest had been exhausted; the length of this delay meant "Supply"s refit was finished before "Sydney" was deployed, and the oiler was sent instead. "Sydney" visited Singapore in March, returned to Australia, and sailed to New Zealand in April: she participated in training exercises during both visits. The troopship was then involved in a joint warfare exercise in Jervis Bay during May.