GPMU regional officer Tom Lowe said 150 employees at the Kidderminster printer were being made redundant, without any formal paperwork being issued.
The company had taken the decision to proceed with the closure and redundancies, following talks with TPL's owner Singaporean media group Times Publishing, and GPMU officials last week.
Lowe said delays in the paperwork for those being made redundant were due to Singaporean management wanting to see all the figures before proceeding.
"It's a disgrace the way the workforce is being treated," he said.
TPL announced it was to close its Kidderminster plant last month (PrintWeek 11 March), a decision that was announced to its workforce by GPMU officials.
Publishers including Future Publishing, Haymarket, Reed Business Information and IPC have since moved their titles to other printers following the company's decision to close.
The GPMU is still investigating taking legal action against TPL, for what it termed as a breach of the 90-day statutory consultation process.