Miller-Heidke's dazzling performance in the first semi-final of the competition in Tel Aviv-Yafo, Israel, on Wednesday morning was a critical stepping stone in Australia's Eurovision campaign.

The result confirms Miller-Heidke's mix of opera, pop, acrobatics and Glinda-the-Good-Witch-inspired whimsy has won the backing of both the "televoting" TV audience and the professional juries who score each country's performance.

Points from both the audience and the jury are merged to cull 35 semi-finalists down to 20.

Those countries then advance to the grand final to meet the host country, Israel, and the so-called "big five", France, Germany, Italy, Spain and the UK.

In addition to Australia, Greece, Belarus, Serbia, Cyprus, Estonia, Czech Republic, Iceland, San Marino and Slovenia also booked slots in this weekend's grand final.

That means the artists and delegations from Montenegro, Finland, Poland, Hungary, Belgium, Georgia and Portugal are now out of contention and heading home empty-handed.

Each of the semi-finals and the grand final is stage four times: two dress rehearsals, a "jury show" in which the performances are scored by the professional juries and the live telecast show, in which the television audience can vote.

The final scores for each performance are compiled by adding the audience "televoting" and the scores assigned by the juries, but the breakdown of those numbers and rankings is not made public until after Sunday's final.

Since it was selected for the competition in February, Miller-Heidke's song, Zero Gravity, has been one of the standout songs in this year's competition.

And since the Australian delegation landed in Tel Aviv-Yafo last week buzz around the song, and Miller-Heidke's performance, has intensified.

Miller-Heidke has also elevated her performance through each of the public rehearsals and the dress rehearsal and jury show.

According to data compiled from betting agencies, Zero Gravity was in ninth position among the 41 competing countries last weekend and, after Miller-Heidke's stunning performance at the jury show, surged forward into third place, behind Netherlands and Sweden.

There are still 10 grand final slots up for grabs, with Armenia, Ireland, Moldova, Switzerland, Latvia, Romania, Denmark, Sweden, Austria, Croatia, Malta, Lithuania, Russia, Albania, Norway, Netherlands, North Macedonia and Azerbaijan competing in the second semi-final, Friday morning, Australian time.

The 20 winning semi-finalists will then advance into the final to meet the hosting country, Israel, and the "big five", France, Germany, Italy, Spain and the UK.

Among the highlights planned for the grand final is a performance by pop icon Madonna; the 60-year-old pop legend arrived in Tel Aviv on Tuesday night.

In an unusual eleventh-hour twist, Eurovision's executive supervisor Jon Ola Sand told media in Israel earlier this week that the contract with Madonna had not yet been signed.

"We have an artist who would like to participate and who we would love to welcome there but we have not signed a contract," he said. "We don't have a signed contract with her team and if we do not have a signed contract she cannot perform on our stage."

Madonna is in Israel as a guest of Israeli-Canadian billionaire Sylvan Adams, who is paying her rumoured US$1 million-plus fee to perform two songs during the final.

Speaking to US media earlier this week, Madonna said she would not persuaded by calls by the activist group Boycott, Divestment, Sanctions (BDS) to cancel her performance.

"I'll never stop playing music to suit someone's political agenda nor will I stop speaking out against violations of human rights wherever in the world they may be," she said.

"My heart breaks every time I hear about the innocent lives that are lost in this region and the violence that is so often perpetuated to suit the political goals of people who benefit from this ancient conflict," she said.

"I hope and pray that we will soon break free from this terrible cycle of destruction and create a new path towards peace," Madonna said.

The 64th Eurovision Song Contest continues live Friday and Sunday at 5am, and is repeated Thursday, Friday and Sunday at 8.30pm, on SBS.

Michael Idato travelled to Tel Aviv as a guest of SBS