The replacement for Barlinnie situation volition outgo astir £1bn, astir treble the erstwhile estimate.
Justice Secretary Angela Constance confirmed a outgo of £998.4m for HMP Glasgow successful a missive to the transgression justness committee. She besides stated it volition unfastened successful 2028, 3 years aboriginal than primitively planned,
The 1344 capableness situation successful the Germiston country volition adhd 357 places to the wide situation estate, successful an effort to lick problems with overcrowding plaguing Scotland's jails.
Constance said the "significant increase" successful costs - from a erstwhile estimation successful 2022 of £400m - was owed to wider increases crossed the operation sector.
The caller outgo is astir 10 times the archetypal estimation of £100m, which was projected successful 2014.
Constance blamed the emergence connected extracurricular factors specified arsenic the covid pandemic, Brexit and the warfare successful Ukraine.
The justness caput said: "HMP Glasgow is simply a bold imaginativeness for the aboriginal of Scottish prisons that volition assistance trim reoffending, lend to little crime, portion delivering a sizeable economical boost for the metropolis and beyond.
"The caller modern constitution volition regenerate a Victorian-age situation that is nary longer acceptable for purpose. It volition summation situation capableness and alteration however prisoners are rehabilitated, arsenic good arsenic considerably improving unit moving conditions."
Constance told BBC Scotland News it was "critical that we person a a situation strategy that continues to relation effectively" and that the outgo summation was justified.
She said: "It's important to retrieve that the earlier estimates were anterior to the last plan and archetypal plans were based connected a overmuch smaller situation arsenic good and that's earlier we get to the interaction connected the operation assemblage of Covid and Brexit."
The Scottish Prison Service (SPS) has present signed a Stage 2 operation declaration with Kier Construction, costing £683.8m and letting enactment determination from beforehand works to main operation of the project.
A readying exertion for the caller installation was submitted to the metropolis assembly respective years ago, owed to interest implicit Barlinnie nary longer being acceptable for purpose, with onshore astatine the aged Provan state works tract successful the East End past being purchased successful 2020.
The £400m outgo was estimated successful 2019 and past repeated successful an infrastructure concern program published successful 2022, earlier Constance told the transgression justness committee the pursuing twelvemonth that costs were expected to rise.
Teresa Medhurst, the main enforcement of the SPS, said the caller situation would person a "transformative impact" successful supporting and rehabilitating people.
She added: "It is an concern successful our staff, successful those successful our care, and successful Glasgow and Scotland arsenic a whole, arsenic we enactment with our partners to amended people's futures and unneurotic physique safer communities."
Construction was primitively owed to statesman successful 2023.
Liam Kerr, the Scottish Conservatives justness spokesman, said the caller situation was "squandering taxpayers' wealth connected a scandalous scale".
He added: "It is scarcely believable that the costs to regenerate Barlinnie are present acceptable to deed astir a cardinal pounds and that the caller situation won't beryllium unfastened for different 3 years.
"That is simply a full dereliction of work astatine a clip erstwhile the SNP are astir to merchandise hundreds of unsafe prisoners owed to their nonaccomplishment to put successful Scotland's situation property implicit 18 years successful power."
In 2023 Barlinnie politician Michael Stoney warned the situation had go truthful overcrowded that a "catastrophic failure" was possible.
He antecedently estimated a caller situation could chopped reoffending by astir 20%.
He told BBC Scotland News: "The caller situation is designed to beryllium afloat of activity, afloat of engagement. All unit volition beryllium freed up to present straight and physique affirmative relationships that volition interaction people's rehabilitation."
According to the missive sent to the transgression justness committee, HMP Glasgow volition supply a "full regime" for prisoners to assistance rehabilitate them.
It added a scope of "activities and opportunities" volition maximise prisoners' time, portion determination volition beryllium the quality to accommodate much wheelchair users successful a bid to support up with an ageing situation population.
Developer Kier Construction said operation of the situation would supply section benefits including apprenticeships, training, and enactment placements for ex-offenders, with the Scottish authorities estimating the task could make up to £450m of spending successful the section economy.
The SPS carried retired 2 outgo consultancies, which it says recovered the £998m outgo was "typical for the industry."