Newspaper group Trinity Mirror said it was in early talks about investing in a new company comprising assets owned by Northern & Shell, Richard Desmond's group that owns the Daily Express and Daily Star titles.
The British publisher of the Daily Mirror said that no offer had been made and there was no certainty that any agreement would be reached.
A combination would unite the left-leaning Mirror with the Daily Star tabloid and the Express, one of the biggest cheerleaders for Brexit.
The titles rank fourth, sixth and eighth respectively in the UK national newspaper rankings compiled by ABC.
British newspaper groups are battling falling print circulation and weakening demand from advertisers.
Analysts have said consolidation could deliver savings and give publishers breathing space to better monetise their online content.
Richard Desmond established his media empire by publishing specialist magazines, including adult titles like the British edition of Penthouse. He launched celebrity title OK! in 1993.
He bought the Express titles, which also include the Sunday Express, in 2000 for £125m.
Desmond's company owns a 50% in the Irish Daily Star, which is co-owned by Independent News and Media.
