No pies were thrown when Alan Joyce fronted the cameras at Parliament House on Wednesday, but plenty of punches were.

The Qantas boss returned serve not only to the West Australian man who delivered a creamy dessert to his face at a business breakfast, but to his critics on the Coalition frontbench who have insisted he ditch the airline's public support for marriage equality.

"No attempt at bullying us into suppressing our voice will work," a defiant Mr Joyce said, vowing to step up his advocacy of same-sex marriage in response to the pie attack.

"What happened yesterday has reinvigorated me, in actual fact. [It] has really encouraged me to continue to be out there and express my views even more strongly than I have done in the past."