Since the introduction of the Australian Red Cross Blood Service's (ARCBS) new mobile blood collection unit, the Donormobile, in May, the service has noted a drop in the number of donations being made in the Southern Highlands.

"We just don't seem to be getting the same number of donations as before," ACRBS spokesman Richard Webb said.

Traditionally the Southern Highlands has been one of the ARCBS's best collection sites, which is why it visits Bowral every six weeks despite the 12 weeks donors must wait between donations.

Prior to the introduction of the Donormobile, a temporary blood collection unit was set up in Bowral Memorial Hall, where, Mr Webb said, the service would often extend its stay to accommodate all the people willing to donate.