Police Union president George Tilbury has described the "recent" practice of having a single police officer look after detainees in country lockups overnight as "flirting with danger".
Mr Tilbury told a State parliamentary committee a survey of members revealed standards at some police lockups in WA were "poor" and single-officer custodial duties had started.
Outside the hearing, he said budget cuts had led to the fall in the number of regional officers looking after detainees overnight.
He said a minimum of two officers were needed.
"We have grave concerns there is an instruction from WA Police at some regional WA locations that overnight, when detainees are in custody, that it is appropriate for a single officer to look after them," Mr Tilbury said.
"It is a very serious situation. It doesn't take long for the demeanour of a detainee to change and it poses additional risks that we believe are unacceptable."
Mr Tilbury told the committee a doctor needed to be at Perth Watch House 24 hours a day so they could decide whether a detainee was fit for custody and whether they should take medications.
Outside, he said Perth Watch House was "grossly understaffed" and significant resources were wasted on accessing medical services when it could be done more efficiently in-house.
Mr Tilbury also called for changes to be made to the State Government's contract with detention services provider Serco, which he claims allows the contractor's staff to "dump" prisoners at police stations for officers to look after before and after they appear in court.
"It is not a police responsibility and it needs to be changed by Government," he said. A spokeswoman for Police Commissioner Karl O'Callaghan said the commissioner would comment on the issues raised by Mr Tilbury when he gave evidence to the committee this week.
WA Criminal Lawyers Association president Linda Black told the committee it was not uncommon for clients on serious charges such as murder to not be able to speak to their lawyer until moments before an initial court appearance."I don't understand why police have the right to suspend a person's opportunity to speak to a lawyer," she said.