Tui pulling out of Coventry
Tui, which operates the Thomson and First Choice brands, has proposed the closure of its Coventry offices putting 600 jobs on the line.
The travel business said the base at Westwood Business Park would be shut by December next year.
It was part of a long-term strategy to concentrate on the web and transform Tui into an online-driven business, it added.
"The proposed changes are not a reflection on the great work done serving customers by all the teams based in Coventry," a statement by Tui said.
"They are the result of many months of research, consideration and discussion about the future of how Tui UK and Ireland communicates with customers and the conclusions have not been reached lightly.
"TUI UK and Ireland is committed to working with and supporting all staff impacted if the proposed changes needed to deliver the customer centric strategy and enhanced customer contact experience are made."
Some of the workers at the Coventry site are expected to relocate to Swansea and Luton with other roles to be outsourced.
A 45-day consultation process on the proposals is set to begin in October (2014).