GPs have written to NHS managers raising concerns that patients visiting the out-of-hours GP service at Forth Valley Royal Hospital in Larbert share a waiting room with patients attending the secure mental health unit.
Emails leaked to The Herald also reveal the GPs, who started working at the centre four weeks ago, are still not linked to the water supply and have to use portable sinks operated by foot.
When they first moved in, the doctors also complained there was no hand soap and insufficient toilets for patients and staff.
One GP said: "If we were a restaurant providing such inadequate facilities I think we would be closed down."
NHS Forth Valley admits there were some "minor snagging issues", but says these have now mostly been addressed. It stressed a full risk assessment found there were no new security concerns.
The GPs are expecting proper sinks to be installed by the end of the month, but their security concerns remain.
Dr Graham White, a GP in Forth Valley who regularly works in the out-of-hours centre, said: "We have a situation where our patients are mixing directly with mental health unit patients and visitors - some of whom have problems including addiction problems. There have been several incidents where patients and staff have felt intimidated by the behaviour."
In one email, a GP describes a patient, having been discharged from the mental health unit, then pestering a mother with a young child for a cigarette and becoming threatening when challenged by reception staff.
Another email describes a man being escorted from the premises by police and security while a couple with their two-year-old child were waiting to see a GP.
Dr White said there had also been occasions of people shouting and swearing. He stressed the GPs were sympathetic to the needs of the patients with mental health problems; however, they are concerned the receptionist stationed in the waiting room can be isolated. Reception staff have themselves raised concerns.
Dr White said it appeared there had been "no proper assessment" of the facilities before the unit opened on Wednesday, December 11, and staff had had to manage despite the problems during the busy festive period.
In a statement NHS Forth Valley said: "There were a number of minor snagging issues; however, the majority of these have now been addressed and the remainder will be completed by the end of January 2014."
The board said the "mobile hand-washing units" fully complied with infection control criteria and work was under way to install permanent sinks.
The statement added: "The service does share a shared waiting area with nearby mental health services; however, a full risk assessment was carried out prior to the move which did not identify any additional security risks or concerns.
"We are not aware of any incidents where patients or members of staff have been put at increased risk since the transfer.
"We will continue to monitor and review the service."