Sunderland MP Sharon Hodgson has written to a health chief outlining why she is opposing a bid to close three urgent care centres.
Sunderland Clinical Commissioning Group (CCG) is carrying out public consultation on its proposal "Making urgent care work better in Sunderland".
If the plans get the go-ahead, they will mean the closure of primary care centres at Bunny Hill, Houghton and Washington.
Urgent care services would only available at Pallion Health Centre, next to Sunderland Royal Hospital.
The new-look service would see GP practices offering urgent and planned appointments on evenings and weekends, with assessments made via practices or 111.
Patients could then be seen by their own practice or through a proposed extended access service running from either four or five 'locality' hubs in Sunderland.
With the consultation deadline looming, Mrs Hodgson, who represents Washington and Sunderland West, has written to David Gallagher, chief officer of the CCG, recording her formal opposition to the proposals.
She writes: "I remain convinced that these proposed changes will be to the detriment of my constituents."
She refers to a letter she sent to him on July 31, asking a series of questions about usage of the centres, accessibility and the role of the NHS 111 service.
Mrs Hodgson says she received no reply, and says Mr Gallagher has failed to make it "clear and transparent" why the proposed changes are needed.
She says patients will have to travel further to access the care they need, which "will be extremely difficult for some patients, who may have disabilities, or little or no access to transport".
Read more: Councillors back campaign to protect city’s urgent care services
Mrs Hodgson is also concerned at the number of appointments available to patients, saying: "These proposals vastly cut down the hours of accessibility. At 10 minutes per appointment there will be 1,059 fewer appointments made available per week than at present."
She concludes: "I oppose the CCG's proposals, and believe that the three urgent care centres must remain open and accessible to patients, so that my constituents can receive the best possible care close to home."
Ann Fox, director of nursing, quality and safety at the CCG, said when the consultation process was launched that the new service aims to “make it easier for people to get the right treatment in the right place".
“People have told us they find the current system confusing and are not always sure where to go to get the care they need,” she said.
“We want to make it easy and simple to access NHS services wherever you live in Sunderland."
People have until Sunday, September 2, to share their views with the CCG, which they can do via its website here.
The decision on the proposals is due to be made by its governing body on December 20.