A Perth aged care worker has been sentenced to two years' jail after pleading guilty to three counts of indecently dealing with an incapable person.

James Ng'Ang'A Irungu admitted he forced an 83-year-old aged care resident who had Parkinson's Disease and was living with dementia to perform a sex act in March this year.

The incident came to light when the resident's daughter had CCTV cameras installed in his room, Perth's District Court heard.

Irungu, who came to Australia in 2023, had been studying for a post-graduate qualification in mechanical engineering and had been experiencing some financial stress, the court heard.

Judge Alan Sefton said the victim required a significant level of care and was unable to defend himself.

He said Irungu's crime had the "real potential" to undermine confidence in staff at the aged care home, where residents' families had placed significant trust in staff.

"You selfishly betrayed that trust," he told Irungu. "You were in a position of care."

Judge Sefton said he took the need for deterrence into his sentencing.

The man will likely have his visa cancelled and be deported back to his country of origin, Kenya, upon his release.

Sadly, the resident recently passed away.