Armstrong wants Changing Places toilets installed as standard for public buildings.
Alliance Strangford MLA Kellie Armstrong has said Changing Places toilets should be required in all planning applications for all buildings accessible by the public.
The toilets are designed to help meet the needs of people with disabilities who need extra equipment and space.
Strangford MLA Ms Armstrong, who is Chair of the Assembly’s All-Party Group on Disability, has written to the Department for Infrastructure to ask what progress they have made on planning legislation to ensure Changing Places toilets are installed across Northern Ireland.
She said: “Due to a lack of space and adult-sized changing tables, many standard accessible toilets are not fit for purpose. That means many older children and adults have to lie on the floor of a public toilet to be changed by the family or career. It is dangerous, unhygienic and undignified.
“If we are to ensure all buildings accessible by the public are fully inclusive then we must commit to the provision of toilets that can be used by everyone. The only toilets offering full access are Changing Places compliant toilets.
“The Scottish Government recently consulted on proposals to introduce Changing Places toilets into building regulations there. Planners here should install at least one in every public building, which will just mean a simple reconfiguration of existing accessible toilets or ensuring plans for all new public buildings have the space.
“It’s time to provide people with disabilities dignity, and give families and carers the support they need to continue to provide safe care,” added Kellie Armstrong.
