THE battle for this year's Century Batteries Australian GT Production Car Championship reaches a critical stage in round six this weekend at Oran Park circuit, near Sydney, with the two leading contenders desperate to score a winning advantage.

After a runaway start to the eight-round national series, Mazda RX-7 driver Ric Shaw has won only one of his six most recent starts and seen his championship lead under increasing attack from the victor in the other five races, Queenslander Mark King.

Shaw hopes the fast, flowing layout of his home circuit will suit his twin-turbo coupe, allowing a couple of wins to boost his current points tally clear of King, who drives a Mitsubishi Lancer RS Evo V.

"This weekend is a crucial round. I need to get a result and I believe we'll go well - but we're in trouble if we don't because the last two rounds at Calder and Sandown in Melbourne will suit the Mitsubishi more than my Mazda," Shaw said.

Similar contests are under way in each of the championship's five classes, with none of respective points leaders yet assured of taking a trophy for the season.

Victorian David Wood (Honda Integra Type R) and former Newcastle V8 Supercar driver Wayne Russell (BMW) are expected to resume an intense battle they staged for the Hippies Sports Touring class in the previous round in Queensland.

In the Pennzoil V8 Touring class, Scott Loadsman will debut a new Holden Commodore to aid his pursuit of fellow Sydney driver Warren Millett, also in a Commodore.

CHAMPIONSHIP POINTS (after Rd 5): Outright, 1 R. Shaw (Mazda RX-7) 103, 2 M. King (Mitsubishi Lancer RS Evo V) 86, 3 B. Hughes (Mitsubishi Lancer RS Evo V) 59, 4 B. Morcom (Mazda RX-7) 49, 5 G. Kenny (Subaru Impreza WRX STi) 39, 6 G. Deane (Subaru Impreza WRX STi) 34; Autobarn High Perf., R. Shaw (Mazda RX-7) 103; Hippies Sports Touring, D.Wood (Honda Integra Type R) 118; Pennzoil V8 Touring, W. Millett (Holden Commodore SS) 92; Pennzoil Six-cyl. Touring, D. Coon (Ford Falcon XR6) 125; Poolrite Four-cyl. Touring, K. Kalaitzidis (Proton Satria GTi) 111.

TIMETABLE: Friday 9.30 am - Practice (30 min.), 12 noon - Practice (30 min.). Saturday 10.10 am - Qualifying (30 min.), 1.30 pm - Practice 1 (15 min.). Sunday 10 am - Race (15 min.), 2.05 pm - Race (20 min.).

Chris Nixon