Rhondda MP Chris Bryant told ITV News that the arrests were 'concerning,' but said he was confident that levels of care in the area were of a high standard.
ITV News understands that all three of those arrested work at Zoar Residential Care Home.
Care and Social Services Inspectorate Wales (CSSIW) last inspected the home in December last year.
The inspection report states that it focused on 'quality of life' and not on staffing, leadership and management at the home.
The report found that out of three respite records inspected, two had no care plans or risk assessments.
It states: "This meant that staff may not always be aware of people's choices and preferences as to how they would like their care to be delivered, what their preferred routines are or how they like to spend their time.
"Staff only had the social services unified assessment to inform them of people’s care needs. This is unsatisfactory as the assessment does not give details as to how care is to be carried out, only that there are particular needs."
Three people have been arrested following an incident at a care home in Tonypandy, police say.
Two men, aged 27 and 72, and a 42-year-old woman, all from Rhondda, were arrested this morning on suspicion of the wilful neglect of a vulnerable adult and perverting the course of justice.
The alleged incident involved an 88-year-old woman who was a resident of Zoar Residential Home in Tonypandy and took place in March this year.
South Wales Police says it is treating the matter as an isolated incident and says it is working with Care and Social Services Inspectorate Wales (CSSIW).
Rhondda Cynon Taf Council is providing support and advice to the home's residents and their relatives.
Firefighters are tackling a blaze at a garage in the Rhondda, which has spread to a furniture factory.
South Wales Fire and Rescue said there are eight crews at the scene in Llwynypia, near Tonypandy.
The A4119 Tonypandy Bypass is closed after an accident between Cornwall Road (Williamstown) and Court St (Clydach Vale).
A smoker from the Rhondda Valley says he's learnt his lesson after he discarded a cigarette butt in the street and had to pay out £560.
Gethin Richards ignored a court summons after failing to pay an initial penalty of £75, so the bill mounted up.
Rhondda Cynon Taf Council says it wants those who drop litter to face the consequences.
Gethin Richards, who is facing a £560 bill after ignoring a court summons for not paying a littering fine, says he's learnt his lesson.
The council said Gethin Richards, 30, from Tonypandy, has to pay its biggest smoking fine yet.
He was prosecuted under the Environmental Protection Act, after being caught by the council's 'streetcare enforcement team.'
He was originally given a £75 fixed penalty notice, but after he failed to pay it the case went to magistrates court, and the total £560 bill also included costs.
Over the last year, Rhondda Cynon Taf Council has recovered £43,950 from fixed penalty notices for acts of 'environmental crime' - which include dog fouling, fly tipping, littering and dropping cigarette butts.
South Wales Police say they believe a fire at the former Clydach Vale Working Men's Club was started deliberately.
Emergency services were called to the blaze at the building known locally as the 'Top Club' on Howard St shortly after midday on Saturday.
The club recently closed after almost a century serving the community. Local boxer and former British and Empire heavyweight champion fought there in 1928.