Two Uber drivers were among drivers attacked in their cars in a spate of early morning assaults across Brisbane's inner city on Monday that marked a violent start to Queensland's Labor Day public holiday.

The same group of men are believed to be behind three attacks on men who were sitting in their cars in Fortitude Valley and Kangaroo Point, in the hours after the all-Queensland NRL grand final clash between the Brisbane Broncos and North Queensland Cowboys.

In the first incident, at 1.50am, an Uber driver was assaulted and his mobile phone stolen, as he sat in his car in Wickham Street in Fortitude Valley.

About 40 minutes later, a group of men punched a man who was also sitting in his car in Wickham Street and damaged his vehicle.