Yes. The agent will submit offers to the Vendor throughout the campaign and the property can legally be sold prior to auction. It is at the vendors’ discretion whether they accept the offer and often they prefer to proceed with the auction if there are multiple interested parties.
If the vendor accepts your offer, you must be prepared to wave the cooling off period, exchange contracts and have your 10% deposit ready as the vendor will most likely want to secure the sale quickly. It’s important to have formal finance approval already granted and to have done your due diligence with obtaining pest and building reports too.