We now know what led to Alan Joyce's pie to the face. And we're not impressed.

The man who shoved a lemon meringue pie into Alan Joyce’s face isn’t a disgruntled frequent flyer but a devout Christian who objects to the CEO using Qantas to promote gay marriage.

Tony Overheu read a statement on Perth radio station 6PR in which he criticised Qantas and other companies including Airbnb, Wesfarmers and Holden for promoting same-sex marriage, which he described as “corporate bullying aimed at social engineering”.

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It has been reported by News Ltd that Mr Overheu is a former Nationals candidate, senior member of the Church of Christ national director of the WA branch of the Full Gospel Business Men’s Fellowship International.

The Qantas boss had a cream pie shoved in his face while speaking to a packed business breakfast in Perth.

He was less than two minutes into a speech to 500 executives at Perth’s exclusive Hyatt Regency hotel on Tuesday when a man in a suit appeared from behind a curtain on the podium and smeared the pie all over his face.

At the time, the culprit didn’t reveal his motive as security pounced and led him away to be arrested while the multi-millionaire CEO was left with an almighty mess all over his face and suit jacket.

"I don't know what that was about, we might take a break for a second," Mr Joyce told the shocked audience who could be heard gasping as the bizarre event unfolded.

After a quick clean up Mr Joyce returned to the podium to applause, joking that he needed the number of a Perth drycleaner.

When asked about the flavour of the pie he replied : "I didn't have a chance to taste it - it was mostly on my glasses".

He said he had never experienced a pieing before but in nine years as the Qantas CEO, "a lot of things happen".

Six years ago Mr Joyce received plenty of unfavourable attention when he grounded the entire Qantas fleet during an industrial dispute but he also turned around the national carrier's financial fortunes, delivering a record $1.53 billion profit last year.

When Mr Joyce, who is gay, was asked if his advocacy on social issues such as same-sex marriage made him a target he said that was pure speculation and police would investigate.

WA Premier Mark McGowan, who later joined Mr Joyce at Perth Airport to announce upgrades that would allow Qantas' recently announced non-stop flights to London and the benefits to WA, praised him for his grace under pressure.

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"Security is important, that person could've done anything and I just urge people not to think that sort of behaviour is normal," he told reporters.

Pieing can be a criminal offence. UK comedian Jonathan May-Bowles was jailed in 2011 after pieing Rupert Murdoch while the media mogul was giving evidence at a British parliamentary inquiry.

A 67-year-old Willetton man arrested in relation to Tuesday's incident in Perth has been charged with giving false details to police and inquiries are continuing.