An NUJ spokesperson said: "If parts of JPI Media are sold to Reach there will be an adverse impact on the market and those employed within it. A takeover of this kind would limit the scope for future jobs in the entire sector.
"Any deal that includes JPI Media’s flagship regional titles would lead to the market being dominated by just two companies - Reach and Newsquest. Both organisations have been relentless in reducing original content and the provision of local professional journalism.
"The union is concerned that decisions on editorial policy and news gathering and practice will be concentrated in the hands of fewer and fewer people and so we are calling on parliamentarians to investigate the lack of media plurality in Britain.
"The NUJ has been warning for years about the trend towards growing media monopolies and the reducing number of companies that own all newspaper titles and their associated websites. It has a profoundly damaging impact on public debate and democracy.
"This latest move is alarming; the NUJ is calling for meaningful engagement with the company and is seeking specific guarantees on realistic, sustainable staffing levels and job security."