Labelling this "an obvious gap", the ACT Greens and RSPCA ACT on Thursday renewed calls for a trial to allow small pets on ACTION buses, as long as they were secured in an appropriate carrier and not impacting on other passengers or the driver.

The capital has the highest rate of pet ownership in Australia, with animals in 75 per cent of Canberra homes.

ACT Greens transport spokeswoman Caroline Le Couteur said the public transport system needed to reflect that, with community consultation in late 2014 showing strong support for the idea.

"As most Canberrans do own a pet of some kind, it must be as convenient and accessible as possible to travel with them," Ms Le Couteur said.

“From an environmental perspective, it’s also important that we do all we can to encourage more Canberrans to shift away from car use."

At present, only assistance animals or guide dogs with an exemption can take the bus, but the proposed trial would allow small, domestic animals on board.

"It needs to be small enough that you can either carry the carrier and put it on your lap or in the luggage rack, which means it can't be a Great Dane," Ms Le Couteur said.

"I think it's entirely possible, if the trial is successful, that larger animals would allowed, on leash, in off-peak times. That seems entirely sensible to me."

Legislation recently introduced by ACT Greens leader and Minister for Road Safety Shane Rattenbury would allow pets to travel on light rail, but Transport Minister Meegan Fitzharris said more work needed to be done before they were allowed on buses.

"That is a policy we continue to work on," Ms Fitzharris said of pets on public buses.

"Obviously, it is one that requires work with Transport Canberra bus drivers in particular."

RSPCA ACT chief executive officer Tammy Ven Dange said many pet owners had been unable to take their pets to the vet because they weren't allowed on the bus.

She said Canberra, and Australia as a whole, were well behind most places around the world in this respect.

"It's not uncommon in other parts of the world to be able to take your pet not only on buses and trains, but also planes," Ms Ven Dange said.

"We believe there's no reason the ACT government, which has been at the forefront of all sorts of animal reform in the last few years, won't be able to achieve this as well."

Animal Medicines Australia backed the idea, with executive director Ben Stapley saying it made sense in a place where three in four households were home to a pet.

"It is important that infrastructure, including public transport, recognises and can accommodate that reality," Mr Stapley said.

"There are many health, social and mental benefits that come from pets and being able to transport those animals is important in helping realise those benefits."