Communities minister Sally Jameson says PC Andrew Harper's killers will not be freed from jail early.
Ms Jameson, on the morning media round for the Government, also appeared to confirm that a solution had already been identified to keep them behind bars.
She made the comment after Andy Burnham asked his Justice Secretary to work through further options to prevent the early release.
"It is important that we find a way, and I'm sure the Justice Secretary will find a way to make sure that PC Harper's killers are not released early," Ms Jameson told Times Radio on Tuesday.
She added: "He's looking for solutions, and a solution's been identified."
Prison capacity under review
Ms Jameson explained that the Government was looking further at whether it could find more space on the jail estate, possibly by reducing the women prison population, to ease overcrowding pressure.
PC Andrew Harper was killed in 2019.
Mr Burnham's move comes amid increasing pressure from PC Harper's family and the police not to allow Jessie Cole and Albert Bowers, who were sentenced to 13 years for manslaughter, to be freed in January under existing plans.
On Monday, Downing Street said it was not possible to exempt one or two offenders convicted of manslaughter from the early release scheme.
However, Justice Secretary Alex Norris will now look at ways to keep a greater number of the most serious offenders behind bars.
A Government spokesperson said the Prime Minister has asked the Justice Secretary to work through further options to keep a greater number of the most serious offenders in prison, including the killers of PC Harper.
Case details
PC Harper was fatally injured when he got caught in a strap attached to the back of a car and was dragged down a country road as the killers fled the scene of a quad bike theft in Sulhamstead, Berkshire, in 2019.
Two out of three of PC Harper's killers, Cole and Bowers, are set to be released half way through their 13-year sentences, after being convicted of manslaughter in 2020.
Some 5,000 people are expected to be released early under sentencing changes, down from 6,000 after some exemptions were announced as part of an urgent review of the scheme to tackle jail overcrowding.
Exemptions were made for those convicted of rape, serious child sex offences and grooming offences.
Last week, the Prime Minister said he had pushed to the very limits of what is possible to do without risking the prison system reaching capacity and collapsing by making these exemptions.
However, more than 880,000 people have signed a petition calling for PC Harper's killers to remain in jail.
No10 said on Monday that manslaughter of an emergency worker was not a standalone offence and it was not possible to simply exclude one or two offenders within the wider category of manslaughter.
According to The Times, a Government source told the newspaper the Prime Minister has never accepted that he would be forced to choose between perpetrators of rape, grooming and the killers of police officers.
Prisons in Britain are close to maximum capacity.
The early release changes were part of the Sentencing Act passed earlier this year that cut the minimum amount of time many offenders would have to spend in prison.
Those freed will face tougher probation conditions, including electronic monitoring, random drug testing and possible bans from driving, pubs and events such as football matches.