Rotorua Museum will remain closed until at least April 2017 when the results of a detailed seismic assessment are expected to be known.

New damage believed caused by the Kaikoura earthquake prompted the precautionary closure of the museum housed in the historic Bath House in Government Gardens on November 18.

Rotorua Museum Director Stewart Brown says a preliminary report from engineers who've started a detailed seismic assessment has reinforced the need to take this action.

'We expect to have a report following that assessment in April next year and at that time we will be able to consider the longer term future of the museum and any work that's needed. In the interests of staff and public safety, the museum will remain closed until further notice.

'Unfortunately, that impacts on the employment of about half of our staff, largely those involved in front-of-house, retail and café operations.”

Stewart says they don't know what the result of the assessment might be, but what is known is the whole process will take longer than otherwise thought. Compounding matters, because of its Heritage 1 status, the integrity of the museum's heritage features need to be protected.

Twenty staff are said to be affected by the closure and are a mix of casual, fixed term, part-time and full-time working in retail, customer service and hospitality roles.

Council will work with affected staff individually through their options which includes taking redundancy, secondment to other divisions within council, or taking up offers of assistance with local tourism operators.

They will also have access to council's employee assistance programme and will receive any other support council is able to provide.

'It's upsetting for everybody that we are having to do this – we have some excellent, very passionate staff and this was the last thing we wanted to have to do. 'We'll need to retain a core of staff as we work through what we need to do to reposition the core museum functions.

'We understand this is an awful time of the year for people to be going through such a process but public and staff safety has to be our key priority.”

The historic part of the museum, the Bath House, has previously been tagged as an earthquake risk and had been scheduled for a detailed seismic assessment.

The new damage inside the building, which was constructed in 1903 and has for many years had cracks which have been marked and monitored, prompted the museum to be closed as a safety precaution.

The damage is limited to the historic, central part of the building, and includes cracking and movement in walls, ceilings, floor slabs, beams and columns. Some existing cracks have also changed.