Speaking in the regional NSW town of Blayney on Sunday, Mr Morrison, formerly the chief of Tourism Australia, backed NSW Premier Gladys Berejiklian’s controversial decision to allow a promotion for The Everest horse race to be beamed onto the world heritage-listed architectural marvel.

The decision has attracted strident opposition from some quarters of the community who say it cheapens the globally recognised building.

“This is one of the biggest events of the year. Why not put it on the biggest billboard Sydney has?” Mr Morrison said.

“I come from a tourism background, these events generate massive opportunities for the state, for the city.”

Fresh from visiting the Bathurst 1000 motor racing event, Mr Morrison said he would “put the Bathurst 1000 on the Harbour Bridge if I thought it was going to get more people there”.

“It’s just common sense and I don't know why people are getting so precious about it,” he said.

“Sometimes I think people have just got to have a bit of a lie down on this sort of stuff. They can get very unctuous about it.”

Mr Morrison rejected suggestions the advertisement was promoting gambling.

“We're talking about an event that is one of the big money spinners for the state. It creates jobs. This isn't about advertising a packet of chips, this is about advertising one of the biggest events that NSW holds.

“Frankly, I thought it was a no-brainer. I can't work out what all the fuss is about.”

Ms Berejiklian’s decision overruled that of Opera House chief executive Louise Herron who had refused Racing NSW’s proposal to light up the Opera House sails with colours, numbers and a trophy to promote next Saturday’s Everest race.

A petition circulated via Change.org in support of Ms Herron had gathered almost 100,000 signatures on Sunday evening.

Ms Berejiklian has defended her decision, saying she was "absolutely confident" the advertising display on the city's most iconic building was "the right thing for Sydney".

The government’s intervention to enable Racing NSW to promote the event on the building followed a hostile interview between Ms Herron and 2GB broadcaster Alan Jones on Friday morning.

Jones told Ms Herron he would speak to Ms Berejiklian within five minutes, and if Ms Herron did not come to the party and agree to the display she should “lose your job."

In her first public comments since Friday's intervention, Ms Berejiklian denied she had caved in to pressure from the shock-jock.

She said the approved design was the result of weeks of negotiations and the government had reached a compromise with Racing NSW after rejecting numerous earlier proposals.

"The version that is going to be displayed on Tuesday is much toned down from what the government was first presented with," she said.

"What we've arrived at is a compromise, I believe a good compromise under the circumstances and that's why the government proceeded.

"There'll be no logos, no names, the only words on there are actually the words of the trophy itself and that is consistent with what has happened in the past.

"I say to people, have a look on Tuesday before you judge it."

Ms Berejiklian said the "vast majority of the display is artistic" with three or four minutes that included the trophy image.

Both the government's decision to allow the horse race to advertise on the building, and Jones' involvement on the matter, has sparked widespread criticism.

Defend the Sydney Opera House, a light-based protest and counter-projection event, has received support from all over the world, including the London-based daughter of the Sydney Opera House architect Peter Hall, Becca Grey.

Ms Grey, daughter of Hall who completed the building after Utzon’s 1966 departure following a dispute with the NSW government, leant her support to the planned protest.

“I would join a protest on my father’s behalf if I was in Australia. It is a terrible idea to do this to the sails, I’m sure he would have hated it, ” she said from London.

Several workers who helped construct the building from 1959 until it’s completion in 1973, including Opus SOH, the consortium which completed stage three of the project, have joined the chorus of anger. Many were angry at Premier Gladys Berejiklian’s decision to overrule Opera House CEO Louise Herron.

One worker, Wilf Deck, an 83-year-old former engineer who worked for Dane Ove Arup, said: “The Opera House is a work of art – we always had a sense when we were building it we were working on something special, like the pyramids, we were not putting up a billboard for ads."

Sydney lord mayor Clover Moore labelled the ads as "blatant commercialism". Willy Hall, the son of Peter Hall, the architect who finished the Opera House, said his father would have been "sickened ... lucky he's not around to see the desecration of our beautiful iconic masterpiece".

Ms Berejiklian said the government's intervention to allow the advertisement was in the best interests of the community.

"I, like everybody else, feel passionate about the Opera House.

"It's an amazing, iconic building and we wouldn't do anything as a government that would jeopardise that."

Asked whether there had been an economic consideration to the government's decision, Ms Berejiklian said: "There's no doubt ... I think last year images of that event were broadcast to 60 million people throughout the world.

"We know it's a drawcard for NSW, we know it's an important event for NSW and that's why the decision was taken."

The Herald revealed two of Jones’ business partners in the horse racing industry have contenders in the Everest race next Saturday, while a horse part-owned by Jones had also vied for a spot.