A Perth taxi owner claims rival Uber illegally set up ranks outside HBF Stadium in Mount Claremont over the weekend.

Zoran Jankulovski said he got a call from a taxi driver on Friday night to say Uber had set up a massive neon sign saying "Pick Up Uber" on Friday night outside the stadium, which was hosting the Perth Darts Masters.

This sign, placed outside HBF Stadium in August, gave rise to allegations of Uber setting up illegal ranks.

Mr Jankulovski said he drove down there to find 20-30 Uber cabs parked at a "rank".

"The government says it's spending money on private investigators to catch them [Uber] out, yet there are 20-30 cabs sitting there in public view," he said.