It's because the results have been so elevated this year that agents have a hard time setting an estimate.

A dilapidated cottage on a small Woonona block, not near the beach, sold for almost $900,000 this week: the old rules of thumb mean little.

"We're increasingly seeing property prices two, three, four hundred thousand above our personal estimate," Ray White Woonona principal Troy Johnson said.

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"After 21 years in real estate I've prided myself in being quite exact with pricing of properties - however this year prices have increased so quickly and rapidly that it's now extremely hard to accurately price a property.

"Hence, you'll see most properties now going straight to auction or saying 'contact agent' [instead of listing a price]."

The run-down cottage at 66 Gray St, Woonona, sold for $890,000 this week. The house, on a small and overgrown 409 sq m lot, appeared barely habitable and was described as needing "a complete internal renovation".

The previous month, a pleasant but unspectacular three-bedroom house on 613 sq m on the same street sold for $1.45 million - an increase of 111 per cent over its previous sale price, $688,000 in 2015.

Neither of these are on the beach side of Memorial Drive.

"The highest sale price last year in the area was $3.7 million - this year it's $6.2 million," Mr Johnson said. "That's just four months - 120 days - and it's gone from $3.7 million to $6.2 million. The market moves that rapidly."