Fears that Bicester's new 30-bed community hospital, costing up to £13m, will not be built have been described as "premature".
Banbury MP Tony Baldry cast doubts on the project's prospects when he questioned Prime Minister Tony Blair about health care.
Mr Baldry said: "In Bicester, there will not now be the new and enlarged community hospital that ministers promised us from the Dispatch Box, and the future of the existing hospital is in jeopardy."
Mr Blair replied that extra funding for the NHS would solve the problem.
Last year, Mr Baldry collected a petition in Bicester, calling on the Government to ensure there was adequate money for the new hospital.
But the MP discovered that money originally earmarked from the savings gained by the closure of Watlington and Burford community hospitals had been spent already.
His remarks about the new hospital were dismissed by Ian Inshaw, chairman of the North East Oxfordshire NHS Primary Care Trust.
Mr Inshaw said: "I think Mr Baldry's remarks are premature. The PCT is in talks with other providers to the NHS to ensure there are community hospital beds in Bicester. The PCT remains committed to providing hospital facilities in Bicester."
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