A Bronte beachfront home has smashed the suburb’s auction record, selling for $23.5 million in a contest that drew more than 300 spectators and underlined the strength of Sydney’s prestige market.

The architect-designed residence on an 841-square-metre block was bought by a local family after competitive bidding from four eastern suburbs-based families. The auction opened at $21 million and progressed in $500,000 and $250,000 increments before slowing to $10,000 rises in the final stages.