The Scottish Police Federation shared an e-mail from a police officer who said colleagues were being discouraged from claiming overtime by the cash-strapped national force.
Calum Steele, general secretary of the SPF, tweeted a picture of an e-mail in which an officer says police are told "not to be proactive" but to simply do the work they are given.
Mr Steele said the e-mail highlighted the "shameful reality" of police cuts.
The SPF has shared a number of complaints from officers in recent weeks, including claims police are having to supply their own light bulbs and hand soap due to cutbacks.
Police Scotland must make savings totalling £1.1 billion by 2026 and faces a £21m "overspend" on its annual revenue budget this year.
Police Scotland have been approached for a comment on the SPF's latest claims.