Labor's spokesperson for disability inclusion Penny Sharpe was in Wagga to launch a petition calling on the NSW government to better support the planning and funding of fully accessible toilets across the state.

Wagga carer Kerein Mullins says travelling with her daughter Bella can be extremely difficult because of a lack of public toilets which have adequate adult laydown change facilities.

Bella is 22 and has complex disabilities including cerebral palsy. She uses a wheelchair for mobility.

Mrs Mullins said Bella needed to travel regularly for medical appointments in Sydney and Canberra.

After leaving Wagga for Sydney, the nearest suitable facilities are in Campbelltown.

The online national toilet map identifies only 13 fully accessible facilities across the whole of NSW. There are three facilities in Wagga, but none on the highways, Ms Sharpe said.

Mrs Mullins said carers often found themselves in the situation where they had to lay their loved one on the floor of a public toilet, or make do with the back of a vehicle.

"It's something carers should not have to do," she said.

"You make do, but really you shouldn't have to just 'make do'."

Mrs Mullins said the lack of appropriate facilities could be quite isolating for families.

"If you're worrying about where you can change someone, it's another factor into planning your trip," she said.

"We, as able-bodied people, just get in the car and go. We don't think about where we are going to go to the bathroom. But when you have someone with a disability, complex needs, that's really got to factor first and foremost into your trip.

"Once you get onto that highway, you really have to wait until you get there, otherwise you're changing on the floor of a bathroom or the back of a car."

Ms Sharpe said the petition can be signed online at www.pennysharpe.com/offthefloor.

A minimum of 500 signatures is needed to have the government consider the petition's contents.