UPDATED: Qantas pie attacker was protesting corporate support for marriage equality.

The man who hit Qantas boss Alan Joyce with a lemon meringue pie in Perth was protesting corporate support for equality in marriage.

Perth resident and active Christian Tony Overheu on Wednesday apologised for the incident, saying it had put him offside with his family and the law. 

“Lemon meringue appeared to be the softest (and) least likely to do any injury…he’s got a responsible job to do,’’ he told Perth radio station 6PR.

“I see myself as a law-abiding citizen so it’s no joke to do what I did yesterday morning.

 “I’ve sent an email to Alan Joyce, Curtin Uni, Hyatt, offering an unreserved apology for insults, costs, whatever else.”

Joyce has been an outspoken supporter of same-sex marriage and Wednesday reiterated his view that there was a role for companies and CEOs to speak up on economic and social issues.

The Qantas boss recovered quickly from the attack by  Overheu on Tuesday as he put into practice the old performer’s catch-cry  “the show must go on’ during the business breakfast at Perth's Hyatt Regency Hotel.

Overheu walked off the stage and was detained by security before being taken away by police and charged.

AirlineRatings editor-in-chief Geoffrey Thomas, who was a host at the breakfast, said he appeared to be confused.

 “He was slumped afterwards in a chair in a dazed state,’’ Thomas said.

The attack stunned a room of about 500 guests and left the airline boss covered in cream.

Joyce excused himself, saying he didn’t know what the attack was about, and disappeared briefly to clean up before returning to continue his speech to applause and join a Q&A session with Thomas.

"If there are any more pies can you get them over with now,'' he joked after returning to the stage.

“He just made light of it,’’ Thomas said, adding that the airline boss didn’t know the pie's flavour when asked.

Speaking afterward, Joyce said the pie attack was unusual but attributed his calm approach to his experience as chief executive of an airline for nine years.

He said he had no idea about the motive and that was a matter for the police.

Asked again about the type of pie, he said: “I didn’t have a chance to test it because it was mostly on my glasses. I think my issue is that I need a good dry cleaner before I leave Perth so if you have one, please recommend it to me.’’