The proposed cuts will affect staff at the Daily Express, Sunday Express, Daily Star and Sunday Star, a National Union of Journalists' (NUJ) spokesman confirmed to Journalism.co.uk.
The group will make 10 further redundancies from elsewhere in the company.
The company is seeking voluntary redundancies from staff and has entered a consultation period today, the union said.
"It's inconceivable that they can continue to produce competitive newspapers with the level of staff that will remain if these cuts go through," Barry Fitzpatrick, NUJ head of publishing, told Journalism.co.uk.
"During the consultation process we will demand justification for each job that the company is trying to cut."
The latest plans are in addition to 80 Daily and Sunday Express redundancies proposed by Northern & Shell in September last year, to cut the number of staff sub-editors, long-term regular casual sub-editors and other casual journalism staff.
Last year's cutbacks included the introduction of a new working week pattern for sub-editing staff at the paper and a production system, which would allow some staff to write directly onto page templates without the need for sub-editors.
In an email to Journalism.co.uk Northern & Shell declined to comment on the announcement.