The Mirror titles are looking to cut down on use of casual, make night editorial staff work more days and make fresh redundancies.
The company is currently consulting on moving staff from a four-night week to a nine-night fortnight.
The move is understood to affect around 100 production and sport staff.
It is the latest in a series of job cuts at the Mirror titles. Last month, Press Gazette reported that a number of senior editorial figures had been made redundant including: Don Mackay, Euan Stretch, Adrian Shaw and Alun Palmer.
Parent company Trinity Mirror has estimated that it needs to find £28m to cover the cost of civil litigation relating to phone-hacking. However, Trinity Mirror said that the latest costs are not related to this but due to worsening market conditions.
Mirror group editor in chief Lloyd Embley said in an email to staff yesterday: “As you are probably aware, the financial climate is proving to be incredibly difficult. Consequently, we have been challenged to make significant cost savings across all areas of the business.
“Sadly, but inevitably, this means that we have had to look at our editorial staffing costs, in particular the amount of money we spend on casuals.
“As a result, we have today started a consultation process with the BAJ [British Association of Journalists]. We are proposing to change the working pattern for employees in news and features production and also in sport.
“The proposal would mean moving from a four-night week to a nine-night fortnight. We do not underestimate the impact of this change and will consider every option, in consultation with the BAJ, before making a final decision.
“Separately and unfortunately, we are also proposing a small number of redundancies. As always, this will be a horrendously difficult time for all involved.
“Our intention is that staff who are potentially affected will be made aware today. This may not be possible in every case but we will do all we can.
“Clearly, and as usual during a consultation period, we will maintain regular communication with you to discuss all proposals as we progress and consider alternatives and ways of avoiding the redundancies.
“I am incredibly sorry we find ourselves in this position and my heartfelt thanks go out to every single member of staff. This is an amazing award-winning team and I am desperate for us to continue to defy the odds.”
A Trinity Mirror spokesperson said: “We have announced a number of proposed changes to the Mirror newsroom as part of our ongoing company-wide efficiencies.
“The main proposed change is to working practices for news, features and sport production staff as we are consulting on moving to a nine-day fortnight, as has been common across the majority of the industry for some time.
“We are also realising further efficiencies by merging some more support between the daily and Sundays teams.”