The union claimed that the move would dilute the Scottishness of the titles. It said that 19 jobs could be lost at Glasgow, although sources at Trinity Mirror suggest that the number will be less than 10.
Under the plans, Glasgows main library would be transferred to Watford, but would retain six staff, while the copy-taking work would be performed by the PA.
GPMU Glasgow branch secretary David Munro said: For over 200 years these titles have been produced from start to finish in Scotland. This is not about efficiencies, the fact is that these departments are already very efficient.
However, Munro added that the GPMU was prepared to talk to Trinity Mirrors management.
If the administrative staff support industrial action, production at Trinity Mirrors print plant at Cardonald on the outskirts of Glasgow could be affected.
A spokesman for Trinity Mirror said the measures were not part of the companys efficiency programme, which is released today (31 July), but were initiated by subsidiary Scottish Daily Record & Sunday Mail.
The objective is to correct operational inefficiencies in the organisation and to protect the future market position of the Scottish titles, said the spokesman.
The Daily Records average net circulation is 504,500, while the Sunday Mails is 613,000.
Story by John Davies
