A £300m plan to expand Calderdale hospital and down-size the infirmary in Huddersfield has been criticised by a council health watchdog.
A committee of councillors has questioned whether the planned-shake up of hospital services would solve staffing and cash problems.
Calderdale and Huddersfield joint health scrutiny committee issued its report on proposals which include centralising A&E care at Calderdale Royal Hospital.
The most serious A&E emergencies from the two towns would be taken to the expanded hospital in Halifax.
Huddersfield Royal Infirmary would be knocked down and replaced with a smaller hospital designed to carry out planned NHS procedures.
Both towns would have urgent care centres treating minor ailments.
In its report, the committee raised concerns over whether Calderdale hospital could cope with thousands more patients.
It said: “The Committee has serious concerns regarding the capacity and sustainability of the Calderdale Royal Hospital site to support an Emergency Centre and Urgent Care Centre providing services to more than 100,000 people every year.
“The Committee is not assured that the proposals take sufficient account of the continuing rise in demand.”
The report raises concerns that the proposals would not eliminate a multi-million pound budget deficit, and that further changes might have to be made to balance the books.
NHS services in Calderdale and Huddersfield face a £270m funding gap between now and 2020.
The report said: “A key concern is that, unless this is addressed, further reconfiguration proposals will be developed within the medium term that may be less subject to local influence.”
The plan to have A&E on a single site is designed to reduce the number of emergency consultants needed at the hospitals from 20 to 12. But the report said the shortstaffed hospitals might still struggle to recruit enough nurses and other workers.
It said: “The committee is deeply concerned that the plans to address these staff shortages consist of little more than a hope that people will be attracted to work at CHFT under the new arrangements because of single site working and because ‘things will be better.
“The committee is not convinced that reconfiguration alone would address the very real recruitment problems.”
The committee also said it wanted more details on now travel times to hospital could be increased.
It said: “CRH and HRI are five miles apart, but unlike many other areas of the country the topography of Calderdale and Greater Huddersfield often results in areas of congestion that increase the likelihood of delays.”
But it added: “The Committee welcome the planned improvements to the A629 by Calderdale Council and Kirklees Council, which will reduce travel time for ambulances, patients and visitors.”
Calderdale and Greater Huddersfield Clinical Commissioning Groups (CCGs)will meet on October 20 to decide whether to proceed with the proposals.