Ann Widdecombe has claimed that the £20 billion of funding announced for the NHS will "last about 10 minutes".
In June, the Prime Minister announced the £20.5 billion per annum cash injection, which was reiterated by the chancellor of the exchequer in this week's Budget announcement.
However, Ms Widdecombe claimed the money was not enough and that the NHS was "not sustainable in the long run".
"We started off spending a few hundred million, now we're spending hundreds of billions, and it still can't keep up, and that's because demand has gone through the roof," she told talkRADIO's Dan Wootton.
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"We've got a service that was set up on the assumption that demand would decline, and demand is going towards infinity."
Wootton suggested charging "incredibly rich people" who earned over £150,000 a year to see their GP as a way of siphoning more money into the NHS.
Ms Widdecombe dismissed the idea as a "piecemeal reform" that "we don't need", adding that politicians needed the "courage" to propose a new strategy to keep the NHS going.
"They're [politicians] are afraid if they start suggesting they might do something to reform the NHS in any big way then that's electoral suicide.
"We need a lot of courage."