Liberal Democrat leader Willie Rennie has called for Justice Secretary Kenny MacAskill to appear before Parliament to answer claims that the new Scottish police force will have to make further cuts.
Mr Rennie spoke after the Sunday Herald newspaper said it had obtained a leaked document containing figures from the Police Reform Board.
The figures apparently show that the single force, which will operate from April, will have to make £300m worth of cuts in the next three and a half years, while 550 civilian staff would lose their jobs immediately.
Chief Superintendent David O'Connor, president of the Association of Scottish Police Superintendents (ASPS), said he did not recognise the figures, while the Scottish Government insisted it would continue to support frontline police numbers.
Mr Rennie said the leaked figures, if accurate, would see "vital" support staff pay with their jobs to underwrite the police reforms.
The Liberal Democrats were the only one of the four main parties to oppose the merged police force in the last Holyrood election campaign.
Mr Rennie said: "These cuts are even worse than we feared and was set out in the outline business case. The costly upheaval of centralising our local police forces will have a big impact on the effectiveness of the police.
"It's vital supportive staff that are to pay the price for the SNP's costly reorganisation.
"For years we have worked to create police forces with the right level of support staff to help our frontline officers do their jobs.
"The Justice Secretary must come before parliament to explain himself."
Speaking on BBC Scotland's Sunday Politics programme, Chief Superintendent O'Connor said the figures had not been discussed by the police reform group, which he is a member of.
"As a member of that group, I haven't had an opportunity to scrutinise these figures," he said.
"The new policing model for Scotland must comprise police officers and police staff, and obviously we would like to have an early meeting with Mr House and the convener of the new Scottish Police Authority to discuss this particular balance."
A Scottish Government spokesman said: "We have protected, and will continue to protect, frontline police numbers and the 1,000 extra officers we have delivered, which have helped reduce crime to a 37-year low, while the fear of crime has also fallen. We have also given a commitment to no compulsory redundancies among police support staff.
"Police reform provides a unique opportunity to improve services. The new service will eliminate duplication by working more effectively and efficiently, saving £1.7bn over 15 years and supporting a single chief constable and one senior management team.
"It will be for the new chief constable and the Scottish Police Authority to determine the balance between police officers and police staff in the new service."