Dainere's Rainbow Brain Tumour Research Fund and Go Gold have joined forces to launch the bus in Childhood Cancer Awareness Month, to continue the work of Canberra teenager Dainere Anthoney.

Fifteen-year-old Dainere passed away in 2013 after an extended battle with cancer, but not before working tirelessly to help fund a cure for paediatric brain tumours through research at the Sydney Children's Hospital Randwick.

She wrote two books, the funds of which went to cancer research. Senator Seselja also launched Dainere's first book and helped promote her second book as well.

Qcity Transit donated the bus and the advertising as part of a five-year program to support Dainere's Rainbow.

TransitGraphics did the graphic design and the application of the graphics to the bus was part-sponsored by Screenmakers Queanbeyan.

Senator Seselja said he had received a bit of a ribbing from his colleagues for launching the bus, given his opposition to the commissioning of two other rainbow buses in Canberra.

The other buses are part of an ACT government-sponsored campaign for people to vote 'yes' in the upcoming postal survey on same-sex marriage.

Last month Senator Seselja criticised the government for funding a pro-marriage equality push when no federal funding would be allocated to either side of the debate.

Senator Seselja said on Wednesday he had already copped a few "friendly digs but it is what it is".

He said it was vital people supported brain cancer research, if scientists were to make the same strides that have occurred with breast cancer in the past few decades.

"I go back a few years with Dainere before her death, her family and the foundation," Senator Seselja said.

"Paediatric research in this area is so critical because unfortunately we haven't made the progress we have with other cancers and it's still a massive killer in Australia.

"Dainere was a really inspiring human being. Her suffering she turned into something positive. It was great suffering, as those who suffer from brain cancer know it's a terrible disease, but she turned it into something positive.

"It's an area we need much investment in and I'm hoping people get behind the foundation."