Zac Rennick is urging his players to rid themselves of the discipline issues which they have suffered in recent weeks as the Macquarie Raiders look to head in the Group 11 finals in form.

The Raiders have fallen to consecutive losses against CYMS and Macquarie and head to Spooner Oval tomorrow to take on a Forbes side that has come alive in the second half of the season and won three of their past four matches.

Ill-discipline has hampered the Raiders' momentum with a number of penalties and sin binnings occurring in recent matches. Rennick said his side was focused on cleaning up that aspect of their game tomorrow.

"We've had a meeting about it during the week and we said these penalties are hurting us, it's just about improving attitude as much as the discipline," he said.

"Giving away penalties and having a guy in the bin for 10 minutes kills us, we need to improve that and it's always a tough trip to Forbes."

The trip to take on the Magpies has often been a bogey one for the Raiders in recent years and Rennick admitted his side would have to be right on their game to return home with the points.

The battle up front is shaping as a key contest with Forbes big men Zac Meritt, Ben Robinson and Pat Rudd going up against the likes of Rennick, Anthony Egan and Dylan Hill.

"They're a big-sized pack but we're a pretty decent size too so it's a matter of getting on top there and that's who'll have the upper-hand," Rennick said.

Adam McDermott misses out again with a knee injury while Perry Meredith is also out after injuring his shoulder in last week's loss to the Cowboys.

With finals quickly approaching and Macquarie sitting third and only two points ahead of Nyngan, who enjoy the bye this weekend, Rennick knows his team have to return to top form to ensure they give themselves the best possible chance come finals.

"I'd just like to see us get our consistency back and play some good hard, disciplined footy," he said.

"You don't want to change too much structure this time of year."

The action at Spooner Oval tomorrow begins at 11.30am with the under-18s while first grade starts at 2.30pm.