The 25-year-old Werribee man was allegedly attacked by another wedding guest at Croatian Catholic Centre on Fitzgerald Road in Sunshine West about 12.30am.
He was in a critical condition at the Royal Melbourne Hospital after undergoing surgery today.
The centre’s venue managers have told 9News 700 guests attended a wedding at the venue last night, with five extra security guards hired for the occasion.
9News understands the venue has also been left with $10,000 worth of damage after the wedding, including toilet seats being ripped off toilets.
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Police have said the exact circumstances surrounding the alleged stabbing are yet to be determined but they believe it was targeted.
No one has been arrested.
Anyone with information should contact Crime Stoppers.