The move by Reach was seen as clearing the way for fellow regional publishing giant Newsquest to take over JPIMedia, which has been up for sale since the summer.
According to the FT, Mr Montgomery was invited in for detailed takeover discussions by JPIMedia on Saturday.
Newsquest has declined to comment on the FT’s claims, but National World has now confirmed its interest in buying JPI.
“The company confirms it is contemplating several acquisitions and has approached JPI following speculation that the sale process for the regional titles had not completed,” it said in a statement.
“There is no certainty that any transaction will proceed. A further announcement will be made as appropriate in due course.”
National World was formed in the summer as a new takeover vehicle with the aim of building a stake in the UK newspaper sector.
Mr Montgomery spearheaded the purchase of Northcliffe Media by Local World, a consortium of regional newspaper publishers and investors, before the company was sold to Trinity Mirror – now Reach – in 2015.
It follows proposals for redundancies at the rival Herald and Times titles, currently owned by Newsquest.
John Toner, NUJ national organiser, said: “Journalists’ jobs being threatened at any time is worrying, but at this particularly febrile time in our country’s politics, it is more important than ever that we have people to hold power to account.
“Just because these cuts have been announced at one publishers titles, does not mean that it does not affect other parts of the Scottish media.
“There are many rumours regarding the upcoming purchase of the JPI Media titles, and staff there are equally concerned that any future owner may wish to implement similar cuts after the acquisition.
“We remind any potential owner that it remains the position of the joint chapel in Edinburgh that any threat of compulsory redundancies will trigger a ballot for industrial action.”