Vic paramedic swapped fentanyl for water

One long-serving paramedic has been stood down as police investigate the theft of the drug fentanyl from vials using a syringe, before it was replaced with water.

The 47-year-old Donvale man was interviewed by police on 5 October and released pending the application of a summons.

A second paramedic was arrested and interviewed yesterday morning after police executed a search warrant at a South Melbourne address.

The 40-year-old man was also released pending summons and he was expected to be stood down, an Ambulance Victoria spokeswoman said.

A Victoria Police spokeswoman said police were investigating allegations of theft from a number of Ambulance Victoria stations.

"As the investigation is ongoing it would be inappropriate to comment further at this time," the spokeswoman said.

Ambulance Victoria chief executive Greg Sassella said "many hundreds of patients" were affected.

"We have been able to identify