Success story ... <em>The Voice</em> mentors: Seal, Joel Madden, Delta Goodrem and Keith Urban.

Success story ... The Voice mentors: Seal, Joel Madden, Delta Goodrem and Keith Urban.

Not since Australian Idol's first season - in which Guy, Shannon, Cosima and Paulini faced off for the final honour (and the record contract) - has a TV talent show stopped the nation in its tracks.

But Monday's epic finish for The Voice, which is expected to set TV ratings records, is dominating the national conversation. Forget politics and sport, all anyone wants to know is whether Karise, Sarah, Rachael or Darren will win.

Nine's director of program development, Adrian Swift, refuses to predict the result in ratings terms, though most commentators are expecting the finale to top the three million viewer mark easily.

''I will never be quoted predicting a number for the final,'' Mr Swift says. ''We have made a great show where really great people have done extraordinarily well. If I get over two million I will be deliriously happy.''

That's not an ambitious number. The weekly editions of The Voice have commanded around two million viewers. The final program, which will attract fans, detractors and the curious bystanders, should draw significantly higher than that.

The closest comparative would be the top-rating second season of MasterChef Australia. That drew an average weekly audience of around 1.7 million and on its final night attracted 3.5 million for the show and 3.9 million for the winner's announcement. (The two parts of big finals are ''coded'' separately for ratings purposes.)

Inclusive of regional ratings, that MasterChef finale had a total national audience of around 5.7 million.

Mr Swift concedes the show has been a huge winner for television generally, and specifically in rebuilding the audience's trust in Channel Nine, which has seen serious audience regrowth following The Voice's success.

It has also, for the first time, clawed back a large chunk of the ground it lost to the Seven Network in the past few years.

''I don't mean to over egg this pudding, but this has been a great show for television,'' he says. ''It's not like My Kitchen Rules or other shows with confected reality. Our show is what you see on the telly. That's what happens in real life.''

The success of The Voice is amplified by the fact that few expected it to be an enormous hit.

Obviously only one of the four finalists - Karise Eden, 19, Sarah de Bono, 19, Rachael Leahcar, 17, Darren Percival, 40 - will win. But Mr Swift says Nine and the production company Shine have a duty of care to all four, particularly the three teenagers.

''We are very careful to look after them,'' he says. ''Darren doesn't need me, or [producer] Julie Ward, really, but the other three do need some looking after in the great, ugly world that is music and TV.''

The winner walks away with a recording contract with Universal Music. The three runners-up will get a cash prize, which is not part of the format internationally and was organised only this week.

''Once we're off air, we want the winner of this competition to go on to release a hit single, and be a happy, robust, creative person, and if they're not, it reflects very badly on the show,'' Mr Swift said.