A report on wheelchair services is due to be completed within weeks
Ministers have been urged to ensure that no-one in Wales has to wait longer than a year for a wheelchair.
Conservatives criticised "unacceptable delays" in providing wheelchairs for children, while Liberal Democrats urged a "minimum standard" for adults.
Health Minister Edwina Hart said she was concerned by the length of time some patients were waiting.
She said a review currently underway might recommend standards for the service across Wales.
Conservative social justice spokesman Mark Isherwood said that "unacceptable delays are leaving disabled and vulnerable people in pain and without the equipment they need to improve their quality of life".
"The health minister herself is on record as saying 'equality of access to all services is key' - we share that sentiment," he said.
"We share the concerns of Disabled Children Matter about the impact of these delays on the well-being of disabled children in Wales.
"Equality means disabled children having the same opportunities as non-disabled children in their daily lives," Mr Isherwood added.
Lib Dems called for a "minimum standard" for adult wheelchair provision, ensuring that no-one would have to wait longer than a year for a wheelchair.
'No recognised standards'
In a statement Ms Hart said: "I am concerned about the length of time some patients are waiting for their assessments and receiving their wheelchairs.
"The provision of wheelchair services falls primarily to the Artificial Limb and Appliance Service (ALAS), which is not an all-Wales service but is based around two centres in Cardiff and Wrexham.
"There are no recognised standards for wheelchair services for adults in Wales, however a review into the provision of wheelchairs and specialist seating is currently under way in Wales, where a possible recommendation may be the establishment of standards for the service across Wales.
"Senior Welsh Assembly Government officials are working with health professionals and other key stakeholders and service users to review the current provision, identify any gaps and consider how it can be improved."
Ms Hart said she would be receiving the report from the review this month.
Last March, long waits for specialist wheelchairs were criticised as "disgusting" by patients and parents in north Wales.
A total of 53 adults and children were waiting for an assessment to allow them to receive wheelchairs.
One child had been waiting for 20 months and the North Wales NHS Trust said it had cut times and was aiming to ensure no child waited more than a year.