Virgin Australia typically reserves the forward seats on flights for their Platinum, Gold and Silver level customers, enabling their frequent flyers to choose the best seats.
This all changes exactly two days prior to departure, where at exactly 48 hours before the flight departure (or T-48 in aviation language) the majority of unallocated seats in the reserved sections of the plane are opened up to other flyers.
Then at 12 hours before the flight departure (or T-12 in aviation language) any remaining reserved seats released to all flyers!
Use this APP to calculate both the T-48 and T-12 times so as to know exactly when to check your seat selection for flights!