Pinderfields Hospital has been turning ambulances away because of delays and bed shortages in accident and emergency.
Patients are being diverted to Dewsbury and District Hospital for treatment for treatment at times when Pinderfields is too busy.
The problem first emerged a year ago, when figures revealed 146 “ambulance diverts” between the two hospitals in 2012 and 2013.
Now new figures show ambulances were diverted from Pinderfields to Dewsbury on 70 occasions in 2014.
But despite Dewsbury taking the extra patients, Mid Yorkshire Hospitals Trust still wants to downgrade the town’s A&E department and centralise emergency care at Pinderfields.
Normanton MP Yvette Cooper said: “This is a serious problem. Being sent from Knottingley all the way to Dewsbury in an emergency can be a nightmare both for patients and their families trying to visit.
“We desperately need more GPs, more nurses and support for social care to keep people out of A&E.”
Figures released under freedom of information rules show that on December 9, ambulances were diverted for eight hours because there were no beds at Pinderfields.
On September 20, there were 72 patients waiting at Pindefields A&E and a three-and-half-hour wait.
There were “minus beds” at Pinderfields on three occasions last January.
Mid Yorkshire’s director of operations Neil Clark said additional beds had been added at Pinderfields to reduce diverts.
He said: “We have, though, seen a four percent increase, year on year, in the number of ambulances coming to our hospitals, with a 10 per cent increase for December.
“Despite the increased demand on our service, these figures show that there were just five diverts in December.”
The A&E changes include more new beds at Pinderfields to prevent diverts, he added.
Last March plans to downgrade Dewsbury A&E and send patients to Pinderfields were referred to health secretary Jeremy Hunt over fears the hospital would struggle to cope with more patients.
Mr Hunt ruled that the plans were safe because extra services were being provided to treat patients outside of hospitals.
Since that time Mid Yorkshire has appealed for people only to go to A&E in a genuine emergency after rising demand on services.
People are asked to seek help from NHS 111, walk-in centres, GPs and pharmacists.