Peter Bowden, who works at the Oliver Lodge home in Saskatoon, says residents are at risk of skin infections because they are left in soiled diapers and bedding for up to 10 hours.
"Several do cry at night when they are that uncomfortable. Some just stay awake and stare at the ceiling," Bowden said Monday.
Understaffing means that residents are only changed once a night when they should be changed at least twice a shift, he said.
"It can and probably will lead to skin breakdown and if anyone gets skin breakdown it's usually a death sentence at that point."
The NDP raised Bowden's concerns during question period as the latest example of why there needs to be minimum care standards in the province.
Bowden, 61, said he breaks the rules at the care home to change residents on his own. The home requires two care aides to turn and lift each resident, but he said that's not the reality of his job.
"If I'm caught changing them on my own, I face a $240 fine." Bowden says he takes the risk to make residents more comfortable.
Bowden has worked at three different care homes in Saskatoon over the last 11 years.
"I've witnessed an awful lot of abuse ... it's the fault of short-staffing."
Health Minister Dustin Duncan has said understaffing isn't a widespread problem at facilities across the province.
A government spokeswoman said the number of continuing care aides at Oliver Lodge has more than doubled since 2006.
Duncan said the issue is about more than just staff numbers.
"This is about changing how we interact with our residents."
The ombudsman began an investigation in November following the death and alleged mistreatment of a senior at a Regina care home.
Margaret Warholm lived at Santa Maria Senior Citizens Home until her death in October 2013. Medical records show Warholm lost almost 14 kilograms in a year and had compression fractures in her vertebrae. She also had a large bedsore on her back that her family believes could have been prevented.
Ombudsman Mary McFadyen said in January that her office had received about 35 complaints related to care in long-term care facilities since her investigation started.
She said the complaints are about poor quality of care, low staff-to-resident ratios, a lack of accountability and poor communication.
Opposition NDP Leader Cam Broten, who has repeatedly criticized the government's stance on seniors care, said the government is dismissing concerns.
"When we hear these incredible ratios, especially at night time ... one care provider for 30, that's just unbelievable, and it's not right," he said.
"I've been hearing similar stories all over the place ... care providers haven't always felt free to come forward and share those concerns."