Thief wearing 'Friday' underpants robs servo on Wednesday

An armed robber wearing underpants marked 'Friday' has been momentarily thwarted by a service station's automatic doors in Melbourne's north.

He entered the Reservoir store armed with scissors on the night of last Wednesday, jumping the counter and stealing cash and cigarettes.

But the front doors failed to open when he tried to flee and he spent several minutes in full view of CCTV cameras trying to activate them.

He then tried to smash the front doors before finally managing to open them.

Police have released images of a man - who was wearing underpants marked "Friday" - they believe could help with their inquiries.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000.