Strangeways prison is currently on lockdown amid claims inmates haven't been allowed to shower or exercise for several days.
The Manchester Evening News understands prisoners have been confined to their cells since Monday (6 June). Families have also been banned from visiting inmates at the Category A jail in Cheetham Hill until Friday (10 June).
Relatives say they've been informed by family members inside the prison that they haven't been allowed out of their cells for any reason and are having food brought to their door.
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One woman, whose 19-year-old son is currently an inmate at the jail said he told her that prisoner's mental health was starting to deteriorate and that the mood inside had become "very tense."
Speaking to the M.E.N, she said: "My son rang me last night to say the prisoner's mental health is deteriorating quite quickly. They say they haven't had showers and are being delivered one meal a day to their cell.
"He said they haven't had fresh air since last Wednesday. I know they are all in their for crimes but they do have human rights and this really isn't good for their mental health.
"Visits have been suspended from Monday until Friday apparently due to maintenance but my son and other prisoners have said they haven't seen any work happening at the prison.
"It's been bad enough but because of the bank holiday it will be about eight or nine days now without any visitors. He says prison officers have been going in to search people's cells."
In a post on Facebook, charity organisation Partners of Prisoners (POPS) said: "POPS have recently been informed that HMP Manchester will be closed for social visits 6th - 10th June for maintenance reasons. If this affects you and you require any support please get in touch with the POPS' Team who will be happy to help."
Another woman, whose partner is also an inmate, said she'd been told prisoners had been locked down for four days and also claimed they had not been able to shower or exercise.
She claims when she rang the prison she could hear alarms going off in the background, and the sound of prisoners kicking their doors.
Another man, whose friend is serving time at the jail said: "They got a letter last week to say the prison was going into lockdown and it was expected to last a week might take longer. He has been behind his door for five days.
"The person I know said today will be his sixth day without a shower. The prison guards are bringing meals round to their cell and they are not even letting them out for dinner. He says it's doing his head in. He said his head is starting to go.
"Surely they have basic human rights and should be able to have a shower. They haven't even been let out to exercise. They have an in-cell phone system so he's been able to ring me but he can't leave his cell."
HM Prison Manchester is a high-security men's prison and is operated by Her Majesty's Prison Service. It is still commonly referred to as Strangeways, which was its former official name.
A spokesperson for the MoJ said: "An intelligence-led operation has taken place this week to crack down on the illegal contraband that puts prisoners and staff at risk. Visits were suspended temporarily but are expected to resume this weekend, while phone calls to family and friends have been available throughout."
