Shellharbour City Council will replace a memorial sign that was stolen just days before the annual event it commemorates.
The Cities Service Boston memorial marks the heroic efforts of Australian infantrymen who successfully rescued 62 US soldiers from the vessel that was grounded on the Bass Point rock platform in 1943.
Four members of the 6 Machine Gun Battalion lost their lives when a freak wave washed them and six others into the sea during the stormy night-time rescue.
On Sunday, more than 100 people attended a ceremony to commemorate the 71st anniversary of the event at the site. However, the theft of the sign, located just metres from the memorial plaque, was a major disappointment.
Shellharbour Mayor Marianne Saliba said council staff believed the sign was taken last Thursday.
"It is upsetting that anyone would see fit to remove something that serves as a reminder of the young men who paid the ultimate price to save the lives of others," Cr Saliba said.
"This is a hurtful, harmful act that disrespects those involved in the rescue, their families and the whole community," Cr Saliba said.
The council has ordered a new sign and expects to have it installed within the next four weeks.