New Zealander It's A Dundeel has been handed a golden opportunity to establish himself as Australasia's champion racehorse by winning Saturday's $3 million Cox Plate.

Having inherited favouritism following the shock scratching of Atlantic Jewel soon after acceptances on Tuesday, It's A Dundeel will have few challengers for the title if he wins the race regarded as Australia's best.

And the confidence of trainer Murray Baker suggests he will.

It's A Dundeel assumed the top line of betting at $4 after Atlantic Jewel was declared a non-runner at the end of a morning of drama and intrigue at Moonee Valley.

No clue of the injury suffered by the champion mare was offered by trainer Mark Kavanagh who came to the Valley for the Cox Plate barrier draw.

As Kavanagh was producing an Academy Award-winning performance at the Valley, fellow Flemington trainers Chris Waller and Danny O'Brien made the surprise moves of accepting for the Cox Plate with Foreteller and Shamus Award.

Waller's decision to pay up came in a hurried phone call to stewards only minutes before the acceptance deadline and less than an hour after he declared the horse would miss the race and run in Saturday week's Mackinnon Stakes.

Shamus Award, a maiden and the Cox Plate emergency, hadn't been mentioned among the possibilities and would have been given no chance in the race.

But with Atlantic Jewel out, he gets a shot at some substantial minor prize money.

For Baker, the news of Atlantic Jewel's defection wasn't welcomed, but the possibility it created was.

It's A Dundeel is the only horse to have defeated Atlantic Jewel, beating her fair-and-square in the Underwood Stakes at Caulfield a month ago and shaped as the clear danger to her in Saturday's race.

After a slight setback two weeks ago, Baker said It's A Dundeel had made a complete recovery from the foot abscess that kept him out of the Caulfield Stakes.

"We think he's tightened up a bit. He looks healthy and we're pretty happy with him," Baker said.

It's A Dundeel turned in one of the best performances of the public gallops at the Valley on Tuesday morning, easily getting the better of the handy mare Let's Make Adeal.

For Baker, the Cox Plate is shaping as the making of a horse whose only rival for top honours was Atlantic Jewel.

"He's shown how good he is. His Derby win in Sydney was spectacular," Baker said.

"The thing with him is that he does it all so easily, he's easy to train, nothing worries him.

"He's relaxed, he's got plenty of speed and he can stay."

One rival trainer who agrees with Baker is Gai Waterhouse who named It's A Dundeel as the danger to her runner Fiorente, even before Atlantic Jewel came out.

"It's a Dundeel, he's the horse to beat," she said.

"He's a very masculine, big strong colt, I'm very impressed with the horse.

"Murray's a lucky man to be training him."