Racing was halted at Allansford's Premier Speedway for more than 45 minutes on Friday night after a medical incident in the crowd.
An Ambulance Victoria spokeswoman said crews were called to the track at 6.20pm and a patient was in a critical condition.
She said multiple crews were still at the track at 7.20pm.
No further details were available before deadline.
The incident on the Warrnambool side of the venue behind the grandstand cast a shadow over the opening night of the South West Conveyancing Grand Annual Sprintcar Classic.
A siren rang out across the facility which halted qualifying about 6.30pm.
It came at the end of time trials for the first group of competitors. Warrnambool's Jamie Veal, a former winner, set the fastest time. Queenslander Lachlan McHugh was quickest in the second group.
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