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."

Mr Joyce indicated he would push for charges against ex-farmer Tony Overheu, 67, who stormed the stage at a Perth business event on Tuesday to lodge a $25.95 lemon meringue pie in the chief executive's face.

Mr Overheu told radio station 6PR he objected to Qantas' support for marriage equality, which he labelled "corporate bullying aimed at social engineering". He said he had been inspired by conversations at a weekend barbecue, where friends lamented "the subverting of our parliamentary process by activists".

"Lemon meringue appeared to the softest, the least likely to do any injury," he said.

The Qantas boss noted an email apology from Mr Overheu, but said he wasn't sure it expressed any actual regret.

Qantas earned the ire of conservatives in March when Mr Joyce was among 20 top business leaders who wrote to Prime Minister Malcolm Turnbull urging him to legalise same-sex marriage without a plebiscite.

Immigration Minister Peter Dutton led the fiery response, instructing Mr Joyce and others to "stick to their knitting" and dubbing their intervention in social policy debates "unacceptable".

On Wednesday, Mr Joyce responded publicly for the first time, insisting he would not be silenced.

"We live in a democracy. We're allowed to talk, we're allowed to be vocal, we're allowed to say what we believe," he said.

"I have every intention to continue to be vocal on those social and community issues. It's important for our shareholders, our employees and our customers. It's called good corporate social responsibility."

Tuesday night's budget flagged $170 million for a same-sex marriage plebiscite under "fiscal risks", in case the Senate reverses its decision to block the legislation.

Mr Joyce said it was very clear to him a plebiscite was "a bad idea" and "would bring out the worst type of behaviours and would encourage the type of [pie-throwing] situation we saw yesterday."

Equality Campaign director Tiernan Brady said the pie episode was a warning to all participants in the same-sex marriage debate that words "can inflict real damage and can lead to incidents such as this".

"Attacks like this have no place in Australian life," he said.