Alex Salmond has avoided a confrontation with opponents of the Scottish Government's same-sex marriage plans and his party's motion to reverse the SNP's historic opposition to Nato at a ministerial "roadshow" event.

The First Minister fielded questions on the controversial issues at Renfrew Town Hall, where cabinet members met voters, after he missed becoming embroiled in a noisy protest by about 200 opponents of same-sex marriage.

Another group of some 60 people were also outside yesterday's event to protest against the leadership-backed motion, which will be heard at the SNP's autumn conference, to drop opposition to the Nato defence alliance.

Inside the town hall, Mr Salmond told a question-and- answer event with members of the public there was no reason to oppose same-sex marriage following the Government's reassurances to religious groups.

He also attempted to reassure defence policy sceptics by saying an independent Scotland would not be obliged to become involved in Nato operations on foreign soil if it remained a member.

Mr Salmond, who was holding the latest in a series of cabinet meetings outside Edinburgh, said: "I don't believe this is a simple matter in terms of there being one religious view on this. You can't say this is the view that all religious people have.

"It will go to a free vote, determined by the conscience of individual members of the Scottish Parliament.

"There will be a consultation beforehand to ensure views are heard. If we can ensure the rights of freedom of practice then I fail to see whose rights are being impinged. I don't think my own marriage is in any way impinged by this change.

A spokesman denied Mr Salmond deliberately avoided the protests and said he had been running late following earlier visits in the town.

Protest leaders claimed he was taken in the building via a side door, but the spokesman said Mr Salmond later "held constructive meetings with representatives of the protesters".

His deputy Nicola Sturgeon, who had been jeered, stopped briefly to speak to some before being ushered inside.

She said: "Whatever decision we take, it is going to disappoint some people. I understand that.

"We have been clear on the protection built into the legislation. No church or individual celebrant will be compelled to conduct ceremonies. I hope we can have a civilised debate on this and work through the issues."

On Nato, Mr Salmond said it was not true that Scotland or any other country would be bound to participate in military operations

He said: "France and Germany did not take part in Iraq. Our position is Scotland would only take part in United Nations- sanctioned operations."

The Catholic Church in Scotland, which opposes same-sex marriage, said Mr Salmond's comments that churches did not need to conduct ceremonies was a red herring.

Spokesman Peter Kearney, who attended the meeting, said: "The focus on ceremonies is unhelpful and it is a red herring. Catholic priests would not be carrying out same-sex marriage ceremonies anyway.

"We are concerned about teachers who refuse to use books that promote same-sex marriage, will they have protection or be sacked, or foster parents who don't agree with it, will they be removed from the register and no longer allowed to foster?

"Will parents be able to remove their child from lessons about same- sex marriage? They can remove their children from religious education just now, but this is not religion, this will be the law."