Cuts to professional library staff across the country should be seen as an opportunity rather than a failure of the service, the culture minister claimed.

Ed Vaizey was giving evidence to the culture, media and sport committee as part of its inquiry into library closures on the day authors and anti-cuts protesters rallied outside parliament.

Vaizey has come under sustained fire on the cuts, which have led to wholesale closures of libraries and a cull of professional librarians across the country.

Campaigners argue that that Big Society "volunteer-led" libraries are unsustainable and will lead to a drop in quality of service and eventual closure.

When asked by Corby MP Louise Mensch what he thought would be the impact of staffing cuts to the service, Vaizey said professional staff remained the "core" of any local authority service.

"Does that mean that there has to be a professional librarian on duty for every moment that it is open? No, I don't believe that it does," he said.

"You have to be realistic and use the resources you have as effectively as possible.There are huge opportunities it's important to reflect upon.

"The depressing thing is that the library issue is stuck in a binary debate about closures and a crisis in the library service and we should be thinking creatively and even open more libraries in community library areas."

Vaizey used the example of a phone box in Philadelphia, which has been converted into a miniature book lending spot.

"There should be books everywhere," he said, explaining government funding of professional staff and access to its book stock could see volunteers opening up their own community libraries.

Steve Rotherham, MP for Liverpool Walton, pressed Vaizey on the fact that most opponents to library cuts see the replacement of staff with volunteers as an easy way for the government to save money while the public provides the service.

Vaizey said that having volunteers run a library was "not a disaster" and that volunteers had always assisted the service.

"It's not a failure of the library service - it's an opportunity for the library service."

He stressed that any local authority's decision to close a library or cut staff would be assessed by the government and would have to be proved necessary, as authorities have a statutory to provide a comprehensive and efficient library service.

Laura Sawfield, chair of the Library Campaign, told the Guardian that the main purpose of the rally in Westminster was to highlight Vaizey's "appalling reluctance to do anything at all".

Research from Unison shows that more than 100 libraries across the country have closed or are solely staffed by volunteers since April 2011.

- Why our libraries are worth saving - Comment.