Journalists at two local newspapers based in Bristol have told BBC News that up to 45 jobs will be cut when their newsdesks are merged.
The 154 editorial staff at the Western Daily Press and Bristol Evening Post, who share a building, were told about the cuts on Friday.
Christina Zaba, of the National Union of Journalists, said: "The NUJ is very concerned about these events."
The two papers are owned by Northcliffe Media which publishes the Daily Mail.
Christine Zaba continued: "People really care about local news and they want good reliable local news.
"If a third of the journalists are removed from the local paper then that news is not going to be the same."
Bob Satchwell, of the Society of Newspaper Editors, said: "These are very, very hard times for local newspapers.
"It is a very difficult problem. Even government minsters are now beginning to realise that they've got to try to find a way of helping those papers.
"Those papers are vital to local democracy and to help people know what's going on locally."
Northcliffe Media has yet to comment on the job cuts.