The Glasgow Cathcart MSP sparked a political row when he criticised the �700m Greater Glasgow Acute Services Review after it received the approval of Health Minister Malcolm Chisholm.

The Tories and the Scottish National Party claim Mr Watson has breached the ministerial code of conduct by speaking out.

Mr Watson represents the Cathcart area

Now the minister for tourism, culture and sport has defended his stance - and stressed that he will not be resigning over the issue.

Speaking on BBC Radio Scotland, he said: "I have got a duty to campaign on behalf of the constituents of Cathcart and they have made their views to me pretty clear.

"They have made their views clear to NHS Greater Glasgow and to the health minister."

Mr Watson said he accepted that the decision had been taken by the Scottish Executive - but believed that his constituents expected him to express a view.

Vote in parliament

"I have two roles to play in this," he said.

"I am a cabinet minister and I am also a constituency MSP.

"I will accept the situation as far as the executive is concerned if it comes to a vote in parliament, I am bound by that.

If he is to see this opposition through, if he is to be a real part of the campaign, then I think he must do that from the back benches

Nicola Sturgeon SNP health spokeswoman

"I don't think I would serve any purpose by resigning."

His comments came as opposition parties attempted to step up the pressure on Mr Watson.

Tory leader David McLetchie told BBC Scotland his party would table a motion calling for a review of the hospital proposals.

"If Mr Watson is so keen on standing up for his constituents he can sign and support our motion and debate," he said.

He said the criticism of the decision was "quite clearly" a breach of the ministerial code.

Hospital proposals

"Mike Watson has undermined the whole principles on which government in this country has been conducted for decades.

"You cannot have two ministers at odds with each other on such an important issue in the same cabinet, so one of them has to go," he said.

SNP health spokeswoman Nicola Sturgeon said she agreed with Mr Watson's opposition to the hospital proposals.

David McLetchie: "Important issue"

However, said there was "a hint of hypocrisy" about his stance and argued that he could not have it both ways.

"If he is to see this opposition through, if he is to be a real part of the campaign, then I think he must do that from the back benches."

Mr Watson in turn accused the opposition parties of "hypocrisy" over the row.

"If they are determined to bring this to the floor of the parliament to force a vote they are not doing this because they want the decision of NHS Greater Glasgow and Malcolm Chisholm overturned, that is not their main aim," he said.

"Their main issue is to embarrass the partnership and in particular the Labour members."

He added that he would be meeting NHS Greater Glasgow and Mr Chisholm next week to discuss the hospital proposals.

Day care

Mr Watson has spoken of his "bitter disappointment" that the centralisation plan. has been approved by the health minister.

The proposals have sparked anger in the south side of the city, where accident and emergency services will be concentrated at the Southern General.

The Victoria Infirmary, which currently houses A&E facilities, is scheduled to become an Ambulatory Care and Diagnostic hospital.

It is planned that patients will be seen, diagnosed and treated on a day care basis.