Already as recognisably Australian as kangaroos and koalas, the social value of the distinctive cultural landmark has leapt nearly 40 per cent in the past decade, according to a new analysis.

Its $11.4 billion in social value, equating to about $425 per Australian, takes in actual revenue, online engagement and how much extra consumers would be willing to pay because an event is hosted there.

Of this estimated value, $5 billion comes simply from its presence – or inherent cultural value – among Australians regardless of whether they visit.

The Deloitte Access Economics assessment comes after $300 million in capital works and the opening of more spaces to the public, as well as broader programming at the world heritage site.

“Over the past decade, we have focused on changing the Opera House for the future and for the better,” chief executive Louise Herron said on Tuesday.

“While our economic contribution has been affected by the pandemic, the social value Australians place on the Opera House has increased by 38 per cent in real terms since 2013.

“As we prepare to celebrate the building’s 50th birthday, it’s wonderful to see the love Australians have for this place is stronger than ever.”

The Opera House is an expressionist masterpiece designed by Danish architect Jorn Utzon that was opened on October 20, 1973.

Nowadays this symbol of modern Australia draws 1.8 million international tourists each year, and this pulling power is the main driver in its $1.2 billion annual contribution to Australia’s economy.

The analysis noted a 2020 Tourism Australia survey showing the Opera House, kangaroo and koala belong in a rarefied category of Australian brands that combine uniquely strong recognisability with highly positive perceptions.

Other national symbols including Uluru, Parliament House, the MCG and Sydney Harbour Bridge were noticeably less likely to be correctly and positively associated with Australia among people overseas.

“It is … one of the strongest brands in the world, making Australia one of the only countries that is recognisable by an arts and culture centre,” Deloitte economist Rhiannon Yetsenga said.

It can also lay claim to being the nation’s most expensive ‘house’ with land and buildings valued at $3 billion.

The Opera House is marking its 50th birthday with a festival of performances, debates and open days through October.