More than 50 jobs at Suffolk libraries are under threat as the service is being forced into a major restructure following two years of serious budget cuts.

Bosses have written to 52 staff telling them that their posts are under threat. Many work only a few hours a week and the job losses amount to 15 full-time equivalent posts.

Formal consultation starts on the job losses at the start of next week and the service restructure is due to be in place by April next year – none of the county’s 44 library branches are expected to close and opening hours should not be affected.

The restructure comes after the library service budget was cut by £230,000 by Suffolk County Council in April – and that followed a £300,000 cut last year.

The service has recently been awarded a £700,000 grant by the Arts Council, but that is for a specific project and cannot be used to subsidise basic services.

Suffolk Libraries Chief Executive Alison Wheeler said this would be the first major reorganisation of the service since 1990: “Then the work of the libraries service was very different to what it is today, but we understand this will be a very difficult time for those going through the redundancy process,” she said.

Over the next two weeks there are a series of meetings for library staff across the county to hear more about the plans and those directly involved in the redundancy process will have a 45-day consultation process.

Ms Wheeler added: “We do of course recognise that this is very stressful for people affected, and we are doing what we can to ensure that they are well informed, and have plenty of opportunity to give their views.

“What we all care about is ensuring that Suffolk’s libraries have a sustainable future.”

The library service was set up as an industrial and provident society in 2012 to run Suffolk’s libraries on behalf of the county council – it relies largely on finance from the county but its buildings in towns and villages have become community hubs as well as places to borrow books.

All the branches have remained open and Ms Wheeler said this remained a key aim of the service as it prepares to restructure itself for the future. Ms Wheeler herself is planning to take early retirement from the service early in the new year once a successor has been appointed.