Two Indian police officers have been suspended after spending a night out on the town with prison inmates.

The pair reportedly spent seven hours drinking with the two prisoners in a beer bar in the western Indian city of Mumbai last month.

Deputy police commissioner S. Jaykumar said the officers signed the two inmates out on the pretext that they wanted to make enquiries, and took them to the bar.

"We found about it from the notes in the station diary the next morning and acted," he said.

"A full departmental inquiry will take place and we'll decide how to proceed based on the findings."

It is the second time recently that Indian police have been caught fraternising with inmates.

Last week, a police raid on a sex district discovered four officers along with a convicted murderer they were supposed to be guarding.