Police Scotland is considering the use of iris recognition technology to help quickly identify when “repeat visitors” are brought into custody.
The national force said the use of scanners would reduce form-filling and allow officers to more easily spot vulnerable people.
While the plans received a cautious welcome, there are concerns over how the force uses and stores biometric data.
The issue is expected to be discussed by MSPs on Holyrood’s policing committee next week alongside controversial plans for “cyber kiosks” which allow officers to override passwords to quickly harvest data from mobile phones.
In an update to MSPs, Police Scotland said: “[Iris recognition] could prove extremely useful to Police Scotland and in particular within its custody facilities. Using iris-scanning techniques would, in theory, reduce queue time, reduce the time custody officers spend form-filling, and quickly identify repeat visitors.
“The benefits of this are obviously clear, however, facial recognition presents considerable risk if implemented poorly without the proper consultation and funding.”
Iris scanners are already used at airports to quickly identify those passing through passport control.
Police Scotland said the plans would be subject to “rigorous scoping” over the next year.
A report published earlier this year by an independent advisory group called for the establishment of a code of practice to cover the acquisition, retention and disposal of biometrics such as fingerprints, DNA and photographs as well as the creation of a new biometrics commissioner.
Scottish Labour’s Justice spokesman, Daniel Johnson, said: “It is absolutely right that Police Scotland look at the possible benefits new technology – including iris scanners – could bring.
“But it is also right that due and serious consideration is given to how this system would operate, including how information would be safely stored.”
Scottish Conservative shadow justice secretary Liam Kerr said he supported Police Scotland’s use of technology.
But he added: “It’s essential this doesn’t leave the organisation open to a data breach, and that its use isn’t extended without full consultation and transparency.”
John Scott QC, who led the independent advisory group on biometrics, said: “This is a new technology of the type we were trying to anticipate in our work.
“It’s exactly the sort of thing that should be subject to proper validation and fall within the remit of a biometrics commissioner.”