Hazel Blears, the Labour party chairwoman, has defended her decision to protest against the closure of her local NHS maternity unit.
The Salford MP insisted she backed the government's wider reforms of the health service, but said it was her job to represent the concerns of her constituents.
Ms Blears joined protesters outside Hope hospital in Salford, Greater Manchester, last Wednesday to voice her opposition to the closure plans, which are part of about 60 'reconfigurations' across England and Wales.
As a close political ally of Tony Blair, her position is embarrassing for the government. Although the prime minister acknowledges the reorganisations are likely to end in ward closures, he insists they are necessary.
Earlier this month, he urged doctors to back the changes, insisting it was better for people to be treated a little further away in a specialist hospital, rather than in a ward close to their home where the necessary facilities may not be available.
However, the reforms have been deeply unpopular and many MPs have joined their local communities to oppose the plan. Speaking on BBC radio this lunchtime, Ms Blears argued that despite her position, she had a duty to back her constituents.
"I did it because local people feel incredibly strongly that their maternity services in Salford.are first class, and they are very concerned about a recommendation that has been made locally that in four or five years time the service would close," she said.
"As a local constituency MP I went along to talk to some of the staff, talk to some of the mums who had babies born at the hospitals and I am quite properly, during this consultation process, making sure that local voices are heard loud and clear."
However, shadow health secretary Andrew Lansley said her attitude was "astonishing", noting the Conservatives had been branded as "Luddites" and accused of being obstacles to progress when they criticised the service changes.
"If Hazel Blears doesn't like what happens as a consequence of government policy in her constituencies then perhaps she should change the government policy or get out of the government," he told BBC News 24.
In September, the government was forced to deny claims that it was playing politics with hospital closures after it was revealed that Ms Blears, health secretary Patricia Hewitt and a Downing Street aide had met to discuss NHS reconfigurations.
It was alleged that "heat maps" were being drawn up identifying where closures coincided with constituencies in which the sitting Labour MP had only a small majority, with a view to minimising the political damage.
But health minister Rosie Winterton insisted at the time there was "no way that there is some kind of political manoeuvring" and said all NHS closures were decided in a "very, very clear process".