Sydney Shares The Melbourne Cup Spirit

Sydneysiders packed big screen venues in Sydney's heart to soak up the Melbourne Cup vibe in a typically carnival atmosphere.

Energy supplier Ausgrid said electricity use across its metropolitan network plunged 100 megawatts - the equivalent of one million desktop computers dropping off to sleep mode - as the city powered down to watch the race that stops a nation.

At Royal Randwick racecourse, more than 25,000 people were blessed with blue skies for the final day of Sydney Spring Carnival.

Two high-profile Sydney identities put their "hard-earned" on Bart Cummings-trained horses.

Former prime minister John Howard risked a "modest amount" on 11th-placed Precedence.

But as he walked down Elizabeth Street in the CBD shortly before the 3pm (AEDT) off, he declined to say how much he had wagered.

"I'm a cautious punter, cautious and infrequent," he told AAP.

Another notable Australian, crooner Kamahl, shared the former PM's bad luck after splitting his $50 between Precedence and Illo, which came in at 19th.

First-time punter Jeroen van Amerongen was one of several hundred cheering punters in Martin Place as he watched his horse Dunaden win in a photo finish.

The 29-year-old consultant turned his $20 wager into $170 by picking the French horse behind gate three.

"I had this feeling it had to be number 3 and it was, although it was close," Mr van Amerongen told AAP.

With his mum Marianne Veerkamp, aunt Joke Veerkamp and his stepdad Ham Essers visiting Sydney from The Netherlands, he now has even more reason to celebrate.

A couple of kilometres away, office workers gathered at Darling Harbour's bars and restaurants to cheer on the Cup field of 23 thoroughbreds.

Anthony Kaelin lost 100 per cent of his investment, after he "copy-pasted" his trifecta bet straight from Macquarie Bank research he found online.

"I donated $60 to my favourite charity - other people." he said.

Ahead of the race, the children's charity Variety auctioned off some Brett Whiteley paintings and a Tour de France jersey signed by Australian champion Cadel Evans at a Melbourne Cup lunch for sick and disabled children.