Despite unusual circumstances, the 23-year-old will be the rider to beat over 40 laps of the 1.1km Sturt Street circuit. 

Ewan has won the past two criterium championships and as one of the world's top sprinters is confirmed already for his Tour de France debut in July.

"When you've won it twice in a row and you're one of the fastest guys in the world, you have to come away with the national jersey or it's a loss," said Mitchelton-Scott team director Matt Wilson.

Ewan has previously started the year as one of the stars at Victoria's Bay Classic criterium series.

The Bay Crits were called off this year, depriving Ewan and his sprint rivals of a chance to fine-tune their form ahead of the nationals.

"He'll be confident and ready to go, but certainly that is a factor," Wilson said.

"Usually he'd be going into this race with a few wins already under his belt and be really race-ready, super-confident. 

“But it's also going to be the same for a lot of guys."

Wilson nominated Brenton Jones, who won the Ballarat Cycling Carnival elite men’s criterium on Monday, and Scott Sunderland as Ewan's main rivals in a field that also includes previous criterium winners Steele von Hoff and Anthony Giacoppo.

Another former winner is Ewan's teammate Cameron Meyer, who took out the criterium in 2013 with a daring solo move.

Likewise, Mitchelton-Scott rider Jessica Allen is the defending women's champion and they will also field a powerful line-up.

The criterium is again opening the championships, which this year have been expanded to include under-19 and para cycling titles.

This means there will be no traditional rest day for the program with fives days of racing – culminating in the elite men’s and under-23/elite women’s road races on a remodelled circuit at Buninyong on Sunday.

A bigger criterium program in the CBD on Wednesday begins at 1.30pm, with the under-23/elite women racing at 6.30pm and elite men at 8pm.