ST MARYS police superintendent Greg Peters faced off against commanders from Penrith, Hawkesbury and the Blue Mountains to see which command could donate the most blood.
All four rolled up their sleeves for the Australian Red Cross Emergency Services Blood Challenge at Nepean Blood Bank last Monday.
Superintendent Peters said although the competition was fierce, the end goal of donating blood for a much-needed service was the big win for all four.
"Everyday our officers respond to serious incidents, including road crashes, serious assaults, drug and alcohol-related incidents, and natural disasters," he said.
"For the victims of these incidents, blood donors are their lifeline.
"If each eligible person in NSW gives up just a few minutes of their day to donate blood, many more lives can be saved."
The statewide challenge, running from June 16 to August 15, involves local police, firefighters, paramedics, emergency response workers and volunteers facing off to see who is the most generous of the emergency services.
A trophy will be presented to the local area command that donates the most blood during the challenge period of July 21 and August 8.
Blood Service spokeswoman Elissa King said winter blood stocks were dwindling, and that up to 1000 appointments a week were being cancelled due to donors feeling unwell - most reporting cold or flu-like symptoms.
"We're calling for extra donors to come forward over the next few weeks, with a particular need for O negative blood donors," Ms King said.
"O negative is the universal blood type used in emergency situations, and it is presently the most in demand."
■ Red Cross Blood Service: call 13 14 95 or visit donateblood.com.au