Willett, the top-ranked Australian men's trap shooter and current world number five, enters the events as defending champion and will be looking for a repeat of his 2019 performance to book his place at Tokyo 2020.

The championships run from Monday through to Saturday and are two of four events for shotgun shooting athletes to win Olympic team selection.

While the team isn't officially announced until late March, victory would all but assure Willett a spot.

"I've been busy training over the last month or so and preparing myself as best as I can for that," Willett said.

"I'm obviously trying to put in a good start and follow it through for the two events after this one.

"It will be a long couple months trying to get the selections and qualifications done."

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Selections are based on qualifying scores, which are out of 125 targets for each event.

The top six then move into the final for a shot at the national title.

"Every target counts along the way then it's a matter of trying to finish as high as you can after making the final. That's the goal," Willett said.

"If you can remain consistent over the three to four events (before the Olympics), it will put you in a good position to be nominated.

"The highest score will be the one to get the first spot to the Games, so remaining at the top right the way through is the goal."

Willett finished fifth on Olympic debut in Rio de Janeiro in 2016, but has made the transition from double trap to trap shooting in that time.

"There is more competition in this discipline and the selection criteria has changed a bit since Rio," he said.

"It will be a bit tougher to make it as we head through this selection process.

"Looking back, the last four years has gone pretty quick. It obviously motivates you as well trying to get to a second Olympic Games and improve on the fifth place I had in Rio.

"I'm trying to get better every time and coming through last year being ranked number one in the world (at one stage) adds a bit more expectation as well. I've got to try to manage that and make sure I put in the best performance I can."

Willett admitted the biggest challenge has been contending with the bushfire smoke, which has blanketed the region in recent weeks, including his training base at Mulwala.

"The smoke is pretty thick, so I've had to pick the days to train in," he said.

"We haven't had any bushfires on the farm, but the smoke is pretty bad."

Willett heads to Newcastle on the weekend for training before the trap competition starts on Tuesday and runs through to Saturday.