An investment of £110m, which will come from existing budgets, will be used to convert unused office space, laundry rooms and storage space into cells, the MoJ said.
The justice secretary told the BBC prisoners being released early did not mean “freedom” and victims would have a say in restrictions placed on those criminals.
Asked where clothes would be washed if laundry rooms were converted into cells, Norris told BBC Breakfast: “Of course we’re going to make sure that the prisons can still function properly.
“This is a creative look, as I say, around our estate and being able to use some space that we can re-prioritise.”
Norris said he suspected the number of extra prison spaces created from freeing up existing space within prisons would be “landing somewhere in the middle” of 200 and 900.
But the chairman of the Prison Officers’ Association, Mark Fairhurst, said: “You can create as much additional space as you like, and build as many new prisons as you like, but where are the staff coming from to supervise people? Nobody wants to be a prison officer anymore.”
Prisons in England and Wales are running at 97% capacity.
Under the early release scheme some 4,500 prisoners are now expected to start being let out of prison in tranches from October.
On Sunday, the prime minister told BBC Breakfast anyone convicted of manslaughter would be excluded from the scheme, following a campaign from PC Andrew Harper’s family to block the release of two men convicted over his killing in 2019.
Extra prison space would also be created by deporting more foreign prisoners and releasing some inmates serving indefinite sentences.
Government figures show there were 10,134 foreign nationals held in custody on 30 June, 3,283 of whom were on remand and would not be eligible for deportation.
In the year to June, 5,962 foreign offenders were sent back to their home countries – the highest rate of deportations since 2017 and a 12% increase on the previous year.
