O’Brien will represent Avanti Racing Team and Witmitz Team Budget Forklifts, in the 61st edition of the 16-team, four-stage event, which finishes on Sunday.

The tour kicks off with a 2.5-kilometre prologue beginning at Birrarung Marr on Wednesday night, with cyclists then to travel through regional Victorian locations including Geelong, Ballarat, Bendigo, Nagambie and Arthurs Seat as part of the competition.

After making his Tour Down Under debut in South Australia and recording a seventh-placed finish in the Road National Championships men’s road race in Ballarat last month, O’Brien is confident he can compete for the leader’s jersey.

“There’s obviously a lot of classy riders, but if everything falls our way there’s probably two of our team who can win it,” he said.

“Realistically, my goal is to come away with a stage win, which will hopefully lead to a good result overall.

“In the Tour Down Under I struggled a bit to get in the right position at the right time, but ideally I’ll show my form again here.”

Witmitz – who will captain his team in the tour – believes team-mates Timothy Roe and Michael Vink are good chances to win.

“Basically we go in each day with a race strategy, but you have to be adaptable – my role will be to make plans on the go, look after the guys and make sure we’re on the same page,” he said.

“We’re a very good chance with those two guys, they’re world class riders and both in really good form – it’s a course that will suit both of them.”

Witmitz – who debuted in last year’s event with the SASI Cycling team alongside O’Brien and under former Horsham coach Tim Decker – said he was excited and well-prepared after a frustrating ride in the Road National Championships elite criterium in Ballarat last month.

“I’ve had a pretty good preparation for the tour with good racing in January and February, and had a few weeks in Adelaide training and watching Marko,” he said.

“Ballarat was pretty frustrating for me. It was all looking good and I was in a good position on the final lap but got caught up in a crash – to get 99 per cent done and have that bit of bad luck wasn’t ideal.

“I’m excited for this year, racing for my own team in the Herald Sun Tour is something I’m really passionate about doing.”

O’Brien – who made his Tour debut in 2006 – said he hoped to make use of his knowledge of various stages.

“Arthurs Seat I’ve done a few times, and Ballarat to Bendigo I’ve done a few times before, so I’m pretty confident there,” he said.

“It’s quite a tough one with Mount Alexander, and knowing that climb perhaps I’ll look for a bit of an opportunity there.”

O’Brien said 2014 Road Nationals road race winner and Tour Down Under winner Simon Gerrans was an obvious favourite in a strong field of cyclists.

“Gerrans is the obvious choice and he’s got a strong team, so you wouldn’t discount any of them, but there’s so many good riders who on their best day could be a chance,” he said.

While there is a rivalry between O’Brien and Witmitz’s teams, the former team-mates both agreed there would be a friendly competition between the two of them at Wednesday night's individual time-trial, which Witmitz jokingly referred to as the ‘Wimmera Cup’.

“He’ll be confident for that, but I’m pretty confident for the rest of the tour,” O’Brien said.

“I’m pretty confident that I’m going to roll him,” Witmitz said.