Race 2 at the Thrifty Newcastle 500 has been red-flagged after a start line incident between Declan Fraser and Macauley Jones.
A Safety Car was called initially before Race Control opted for a red flag due to damage to the pit wall.
Jones and Fraser shared the 12th row of the grid, with a replay showing that the latter moved left as he tried to overtake Cameron Hill, who started on the outside of Row 11.
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That led to contact between Jones and Fraser, which turned the #56 Tickford Racing Ford Mustang hard into the pit wall at an access gate, pushing it back.
Walkinshaw Andretti United's Chaz Mostert leads Grove Racing pole-sitter David Reynolds under red flag, while Jones was able to drive the #96 Brad Jones Racing Mustang back to pit lane and is classified on the lead lap in 23rd.
An official was hit and fell when the wall moved back, but is not seriously injured.
Update 15:30 AEDT
Field exits pits after almost 20 minutes under red flag, including Jones.