Sefton Central Labour MP Bill Esterson said he is concerned about the change in status of Maghull's Kennet Prison after it was announced that the jail was to become a "semi-open prison".
The Ministry of Justice has announced it will be recategorising the prison in April next year from a category C to a category D facility.
The move means Kennet will go from a closed prison to becoming a semi-open resettlement facility housing prisoners working towards fully open prison conditions, at which time they will be moved to an open prison.
Kennet will maintain perimeter fencing so prisoners can not come and go as they please, although a government spokesman has told Bill Esterson that regular temporary licences for leave will be granted to prisoners.
These licences are generally granted to prisoners who are carrying out supervised community work.
Bill said he had a number of concerns about the prison after it was announced that there was major overcrowding at the site.
Bill said: "I have raised a number of concerns with the prison in writing, not least about the overcrowding. Recent figures indicate that Kennet was designed to hold 175 inmates, but it currently holds 337. It is officially the most overcrowded prison in England and Wales.
"If the site is recategorised, will Kennet have fewer inmates? If not, how can the prison cope with those numbers in a semi-open prison environment?
"While we are getting assurances from the prison service that there will be no violent criminals at Kennet, we need to know exactly what type of prisoner the jail will house.
"My priority is the people here in Maghull. That's why I am asking the questions that matter now to ensure that the community is safe."
Bill is also pushing for assurances that there will be no redundancies among staff at the prison.
Bill said: "I have been told that there will be no suggestion of job losses and certainly no compulsory redundancies, but given the lower supervision requirements at a recategorised Kennet prison, the Ministry of Justice have indicated that there may be some job movement. they have also indicated that there may be natural wastage and potentially some voluntary redundancies. But they have yet to work out exactly what staffing requirements they will need.
"However, we need to know the exact details of what staffing the prison will need under its new category. We need to know that there is enough staffing to ensure the security of the surrounding community."
The MP is also calling for a meeting with the prison governor to talk through the plans.
Bill said: "There are lots of questions still unanswered about the Ministry of Justice's plans for Kennet.
"I am arranging to sit down with the prison governor to put to him questions which I have have and questions which members of this community will have. I will also be putting the same questions Tory Prison Minister, Crispin Blunt who made the decision to change the status of the prison.
"My priority as MP for Sefton Central is to ensure that the concerns of the people of my constituency are heard and addressed and that is exactly what I will do."