When nurse Kylie Strong worked in emergency she saw first-hand how bad things can get when blood supplies dwindle.
"One time we didn't have any blood for a particular person and an urgent call was put out for staff to donate right away," the Port Kembla-based nurse said.
That was years ago, and she still regularly rolls up her sleeve.
"I've been doing it on and off for years now," Ms Strong said.
"Working in the system you see just how desperately people need blood. Often it's not until you hear a call on the radio or see it in the newspaper that you think about it and get in and do it."
Ms Strong yesterday joined health workers to pump up the dangerously low levels of blood.
Wollongong is one of six NSW locations urgently trying to boost its stock after regular donors dropped off during winter months.
The Wollongong Donor Centre is 350 appointments short of what it needs.
Nurses and midwives joined other union members in the Illawarra as part of the Unions for Transfusions statewide campaign.
NSW Nurses and Midwives Association secretary Judith Kiejda said health workers "know all too well how important this is".
"That is why the [union] is very pleased to help organise, with Unions NSW, this campaign across the union movement to lift the number of regular donors in this state.
"I know hundreds, if not thousands, of union members in the Illawarra are keen to do their bit," she said.
"I'm confident union members in Wollongong and across the Illawarra will enthusiastically join this campaign."
Workers took time out yesterday morning to sign up at stalls at Wollongong Hospital and Industrial Galvanisers at Kemblawarra.