Fingerprint officials at the centre of the Shirley McKie case have been offered a deal to leave their jobs.
Unison criticised the offer made to officers who identified the prints
Public sector union Unison described the efforts to remove the staff from their posts as "harassment".
One of the experts told BBC Scotland that she believed she faced the sack if she did not accept the deal.
It comes as the parliamentary inquiry investigating the misidentification of Ms McKie's fingerprint heard from Scotland's Lord Advocate Colin Boyd.
The inquiry also took evidence from the justice minister, who said the £750,000 awarded to Ms McKie was less than the £1.2m the former detective had sought.
The former Strathclyde Police officer, from Troon in Ayrshire, was cleared of leaving a print at a murder scene in 1997.
She received an out-of-court settlement after being found not guilty of committing perjury, when she contested the opinion of experts from the Scottish Fingerprint Service.
Justice Minister Cathy Jamieson told the committee the settlement was made on the basis that there had been a misidentification of Ms McKie's print, but that no malice was involved.
Unison said the officers involved in the case had now been offered early retirement, redundancy or redeployment within the police.
It said the approach was made as part of an action plan to modernise the Scottish Criminal Records Office (SCRO).
Experts Hugh Macpherson, Charles Stewart, Fiona McBride and Anthony McKenna and two colleagues are at the centre of the move.
Ms McBride told Newsnight Scotland said she had received an offer to terminate her employment.
"If it is not accepted, then I believe the chances are to be sacked," she said.
MSPs are examining how Ms McKie's print was misidentified
Anne Russell, Unison's regional officer, said it was "outrageous" the offer should be made in the middle of a parliamentary inquiry into the matter.
She said: "Unless these threats are withdrawn, Unison will be talking to our lawyers, to the staff affected and to the staff as a whole to decide our next steps in backing our members' rights."
Lord Boyd told the inquiry that it was unlikely that any of the four officers who identified Ms McKie's print would be called as experts in court again.
He said any future case they were involved in would be overshadowed by their links to the McKie case.
However, Ms McBride insisted she would not be taking any deal.
She said: "I'm hoping that despite what he (Lord Boyd) said, the decision will be taken to put this off.
"I'm hoping that we will give evidence in court again."
Ms Jamieson was the 38th witness to come before Holyrood's Justice 1 Committee.
She told MSPs the settlement recognised the damage caused to Ms McKie and allowed her to move on.
But she said she also had tried to recognise the "very difficult position" of the four SCRO officers who had identified the print as Ms McKie's.
"I was acutely conscious of the fact these were people's lives we were talking about, not only Shirley McKie and her family but the SCRO officers," she said.
She finished her evidence session by pledging to consider any recommendations the committee makes in its report.