A troubled police control room was unable to receive 101 calls for almost eight hours.
Bilston Glen, which took the initial report of the M9 crash which eventually claimed the lives of Lamara Bell and John Yuill, could not receive non-emergency inquiries from 3.30am until just after 11am on Tuesday.
Scottish Liberal Democrat leader Willie Rennie said a member of the public told him their call to the contact centre, which has suffered staffing issues, went unanswered.
The Mid Scotland Fife MSP added: “The Scottish Government and Police Scotland must make an urgent statement. The public must know how they can communicate with the police when the system is down.
“I first became aware of the problem when a member of the public told me their 101 call had not been answered. I am astonished that after seven hours from when the system went down there has been complete silence from Police Scotland.”
Scottish Labour’s Justice spokesperson Graeme Pearson added: “People need to have confidence that the police will be there when they need them. We have some of the finest police officers in the world, but their reputation has been dragged through the mud because of decisions made by SNP Ministers and the leadership of Police Scotland.
“This news suggests a failure to learn the lessons of the HMICS report into call handling, which exposed systemic, fundamental failings because of the SNP Government’s botched reforms of our police service.
“SNP Justice Minister Michael Matheson can’t do his usual disappearing act here – he should immediately disclose when he knew about this, if it has ever happened before and if he was previously warned that there was a danger of this happening.
“These events suggest that the SNP’s plans to close contact centres in Aberdeen and Inverness are completely untenable.
“When the M9 tragedy occurred, Michael Matheson said that it had nothing to do with a lack of capacity or a lack of resources. The HMICS report showed that to be completely false, today’s events show his comments to be utterly ludicrous.”
Chief Superintendent Alan Speirs, C3 Division, played down the incident at the under fire centre.
He said: “I can confirm that in the early hours of Tuesday December 15, 2015 the Service Centre at Bilston Glen experienced a technical difficulty which resulted in 999 and 101 calls being diverted to other regional service centres. The issue has now been resolved and the system is working normally.
“Police Scotland has robust and tested plans in place for eventualities such as this and I am pleased that they worked extremely well. There was no interruption to the emergency and non-emergency services and no delays in calls being answered or officers being dispatched.
“The public will not have noticed any difference in the level of service they received and I would like to once again thank all our call handlers for dealing with this issue so quickly and professionally.”
An insider with the force said the issue was further evidence the planned closure of the Aberdeen control room should not go ahead.
The source added: “Staff are now sitting in a van waiting to go to Govan and Motherwell where there won’t be any seats for them. It’s pointless.
“If this isn’t an argument to keep Aberdeen open I don’t know what is.”
He added that staff had been put on to minibuses as the force had planned to shift them to Govan and Motherwell centres.