The Kath and Kim star, who encouraged drivers to "take out" annoying cyclists during a sketch on comedy show Good News Week, even offered to take part in National Ride to Work Day next month.
According to The Daily Telegraph, Szubanski said: "The way I expressed myself was appalling and thoughtless. And I sincerely apologise."
She continued: "I was so very saddened to hear of the terrible accidents and injuries that some people have suffered when riding and I feel deeply and truly sorry to think that my comments might have added to their pain."
She added: "When I made those comments I was not thinking that drivers actually target cyclists deliberately. You may think this naive of me but that is the truth."