Semi-final spots are on the line in a massive double-header of Twenty20 cricket in the Illawarra on Saturday.

Corrimal and Keira have a chance to cement their positions at the top of Pool B; they need just one win to earn a spot in the knockout rounds.

The Cougars face Dapto first-up at Reed Park before they take on Keira in a top-of-the-table stoush.

Skipper Robbie Fisher was hopeful qualification could be secured before they meet their fellow high-flyers.

"It would be nice to beat Dapto first-up, then the pressure will be off us when we [play] Keira," Fisher said.

"Ideally it would be nice to win both games and finish on top of our pool.

"Last year we made the semi-finals and just lost to Keira, so hopefully we can go one better this year."

Fisher admitted that the Cougars would meet Dapto and Keira at an ideal time; both clubs have players on NSW Country duty.

Keira will be without run machine Graeme Batty and Jono Cook, while Dapto are missing Dale Scifleet.

Other Pool B action sees Northern Districts play the Lions in the early round in the slim hope of keeping their finals chances intact.

In Pool A, Balgownie and Helensburgh are set to fight it out for the second semi-finals spot as Wollongong leads the table.

Magpies captain Christian Lewis wasn't keen to play down the match's importance.

"It is a must-win game against Balgownie to get us to the semis," Lewis said.

"It is critical to get a good start in the first game so we can keep a high going into the next one against Port.

"Port is a bit of a dark horse, I think. They have a few quality Twenty20 [players] in the competition, so it is definitely going to be tough."