Mr Whippy no soft target in Perth robbery

A soft serve vendor has proven he's no soft target, pulling off a citizen's arrest when a thief tried to rob his ice cream van in Perth's north.

Police allege a 22-year-old man lay in wait for the 40-year-old to park his van in Ocean Reef on Thursday night, before bursting into the vehicle and stealing cash while threatening the driver with pepper spray.

But as he tried to leave the van through the service window he was nabbed by the driver and another man, who detained him until police arrived.

He is due to appear before the Joondalup Magistrates Court later on Friday.