At the height of WWII the cargo ship Iron Chieftain set sail from Newcastle loaded with coke and steel supplies for Whyalla at 10.15am on June 3, 1942.
At 10.30 pm that evening a Japanese Submarine torpedoed the vessel south east of Norah Head light house killing all 13 crew members.
The following afternoon another cargo carrier the Iron Crown was torpedoed off the south coast of NSW resulting in the heaviest loss of life of any merchant ship during the war.
"The merchant ships played important roles during times of war," Newcastle Merchant Navy Memorial Committee chairman Peter Morris said.
"That's why we will continue to acknowledge them and their place in history."
Students from the Hunter School of the Performing Arts and Swansea High School will lead Saturday’s annual memorial service to the merchant mariners killed in defence of Australia.
Read more: Was the Iron Knight torpedoed by accident?
The service will commence at 11am at the Mission to Seafarers Centre Hannell Street Wickham.