Representatives have also accused management of failing to adhere to a dispute resolution agreement reached in 2019, putting a further strain on industrial relations.
Employees will be asked if they want to take strike action and action short of strikes such as no rest day working and an overtime ban.
Management seem intent on picking a fight with RMT members instead of listening and negotiating properly with them
The ballot for train hosts and train host team leader grades will open on Tuesday, October 31 and close on November 21.
RMT general secretary Mick Lynch said: “Our members have expertise in what kind of staffing levels you need on the Caledonian sleeper, both in terms of safety and comfort of passengers.
“Management seem intent on picking a fight with RMT members instead of listening and negotiating properly with them.
“A big vote, and turnout for strike action will send the clearest message to Caledonian Sleeper management that they need to respect the workforce and not renege on agreements with the union.”
The Caledonian Sleeper is a service operated by Scottish Rail Holdings on behalf of the Scottish Government.
The operators have been approached for comment.