The foundation hopes to add to its pool of eight drivers to ease the burden and have a more flexible schedule.
All potential drivers need a Class 2 licence and must be double vaccinated.
"We just want to have a pool big enough where we don't have to rely on the same people every day," Bartley Foundation co-ordinator Caitlin McDonald said.
"There is no minimum requirement. With there being a small group of them, they are having to do this regularly and we are just a bit conscious of that.
"We love seeing it utilised and out in the community doing what is supposed to do, we just want to make sure we have the manpower to meet the DHB's requirements."
The bus removed barriers for people and its presence on the road was a reminder to the wider vaccination mission.
Robert Bartley's son John Bartley said once the Covid-19 rollout was complete, the bus would move into a more general health role, such as visiting schools and wider regions across the Whanganui DHB.
• Anyone interested in learning more can contact Caitlin McDonald at info@bartleyfoundation.org or call her at 027 664 8303.