The house on Schumack Street sold for $2.4 million against a guide price of $1.59 million when it was originally listed.

More than 20 buyer groups registered for the auction and there was a huge crowd.

John Grayson, sales agent for BresicWhitney, said buyer interest was so strong during the marketing campaign that the guide price kept rising.

"There were 66 groups of houses at the first opening, so the guide price went up by $50,000, and then after the second opening we increased the guide price again," he said.

"Before the auction, we thought it could be closer to $1.9 million ...... We never thought it would be much more than $2 million."

The price is understood to be more than $400,000 higher than the seller's reserve price.

The home is being sold on behalf of the original owner, who recently moved into a nursing home and gave her children control of her property.

Mr Grayson said the children, who grew up in the house, were visibly agitated after receiving an unexpectedly high price.

It was also an emotional rollercoaster for the buyer, who had reportedly been looking for a home in the area for some time. It is understood that she is planning a renovation.

"I think the emotions did a lot of bidders a favour. (The auction) has been going on," Mr Grayson said.

The agent noted that throughout the Ryde area, competition among bidders was fierce, as there were few properties for sale.

There was also strong interest from developers in the area, with blocks that could potentially be converted into duplexes, such as the Schumack Street property, being fiercely contested.

Earlier the same day, a larger block on nearby Michael Street sold for just over $2.71 million after 23 bidders registered for the auction.

Auctioneer Chris Scerri said the price was some $231,000 above the reserve, considering the "ambitious" pre-auction sale.

But Mr Scerri added that the area had changed considerably in a short space of time due to growing demand from developers.

Belle Property agent Phil Allison, who owns the Michael St listing, said developers are looking at the area because it is located near numerous employment centres and is cheaper than nearby areas such as Lane Cove.

"Developers are still buying, they're just being more selective about where they buy and North Ryde is seen as a safe (investment)," he said.

Mr Allison said the lower number of listings was directing increased buyer demand to the same properties.

"In 13 years of selling real estate in the area, I've only seen inventory levels this low once, and it was during a lockdown."