The siblings will hit the court for Warrnambool Football Netball Club, which is made up of Hampden league netballers.

The Blues will take on the competition's reigning premier, Colac and District Football League Netball Association (CDFLNA).

While O'Connor lined up for the green and gold last year, O'Sullivan clashed with them in the grand final when she coached Hampden.

Colac and District prevailed 44-37 in the decider.

O'Sullivan was unsure what to expect from CDFLNA and the competition's new side, Colac Football Netball Club, which plays in Netball Geelong.

"They're the unknowns, really, because all the other teams are made up of players from the Warrnambool area," O'Sullivan said.

There are three evenly-selected Hampden league teams - Koroit, Hampden and Warrnambool - in the competition.

The other side in the open division is Warrnambool and District Football Netball League.

O'Sullivan said her side's preparation had been limited.

"All three Hampden teams got together for the first time on Monday night," she said.

"Basically everyone does their own fitness."

She believed playing in state league was extremely beneficial in the lead-up to players' regular home-and-away seasons.

"It's just good to get your netball skills back before the season starts, which is pretty important," she said.

"It's also good for match fitness."

The defender thought Warrnambool looked promising on paper.

"We've got a few older heads in the team and we've got some youth as well, so we've got a good mix," she said.

"I'd hope we could win five games out of the seven."

The seven rounds will be contested on Thursday nights at The Arc, with two weeks of finals to follow. There is also a 17 and under division.

Netball Victoria operations manager Emma Lappin was pleased the south-west was hosting state league again.

"It is a great opportunity for local communities to be involved, to be a part of and support an elite competition in local areas," she said.

Round one action starts at 6.45pm.