Hours were extended again on Thursday, with more than 80 people swabbed for the virus.
A Whanganui District Health Board spokesperson said the centre would open on Saturday and Sunday for the first time since the district was last at level 2 at the beginning of March.
The centre will be open from 8am to midday, and the DHB is asking anyone with the slightest symptoms to present for a test.
"Again, Whanganui District Health Board reminds our community to remain vigilant," a spokesperson said.
"If you are unwell, please stay home. Do not go to work or school. Do not socialise. If you have cold, flu or Covid-19 symptoms, call your doctor or Healthline and get advice about being tested."
Meanwhile, four nurses from Whanganui DHB have been sent south to Wellington to help out with the increasing demand in testing there.
Director general of health Dr Ashley Bloomfield gave those four nurses a special mention at Friday's Beehive briefing, thanking them for joining in to assist the Wellington region.