Two new jails are to be built in south Wales and Yorkshire as part of a £1.3bn government pledge to create 10,000 modern prison places by 2020.
Sites in Port Talbot and Full Sutton, near York, have been earmarked. Two existing jails in Kent and Wigan will also be redeveloped.
The justice secretary said modern jails would help cut reoffending.
But Peter Dawson, of the Prison Reform Trust, said “closing prisons, not opening them” was a better solution.
A final decision on the two new prisons depends on planning approval and “value for money”, the government said.
The two jails being redeveloped – HMP Rochester in Kent and HMP Hindley in Wigan – will both be shut while extensive rebuilding work takes place.
The construction programme will be offset by the closure of a number of older prisons, the details of which have yet to be confirmed.
In prisons in England and Wales, levels of violence, suicide and self-harm are up, staff numbers are down and complaints about overcrowding are widespread.
There have been a number of disturbances at jails in recent months and last year, thousands of staff walked out in protest over health and safety concerns.
Justice Secretary Liz Truss has vowed to overhaul the system, improve the estate and recruit more officers.
She said: “Outdated prisons, with dark corridors and cramped conditions, will not help offenders turn their back on crime – nor do they provide our professional and dedicated prison officers with the right tools or environment to do their job effectively.”
But Mr Dawson, who supports an overhaul of the prison system, criticised the plans, saying: “This massive investment in new prisons is not matched by a credible plan to reduce our reckless overuse of prison in the first place.”
Shadow justice secretary Richard Burgon agreed that the new jails would fail to tackle overcrowding in prisons.
“Simply replacing one prison with another prison doesn’t deal with the overcrowding crisis,” he added.
Last month the UK’s newest prison, HMP Berwyrn in north Wales, opened its doors to more than 2,000 inmates.
The £250m jail, which is Britain’s biggest, contains a health and wellbeing centre, an education block, a sports hall and a multi-faith area.
Plans are already under way to redevelop two prisons in Leicestershire and Northamptonshire.
The proposed new-builds at Port Talbot and Full Sutton will create up to 2,000 construction and manufacturing jobs, the government said.