Figures detailing the explosion in investment in Sydney's property market have underlined Reserve Bank concerns that a wave of speculation is making the property market increasingly unbalanced.

Investors have lit the fuse under the biggest residential property boom in more than a decade and account more than 55 per cent of all new property loans, according to ANZ Bank economists.

Sydney has seen a property surge. Credit:Rob Homer

Official data from the Reserve Bank also shows bank loans to non-owner occupiers are surging at the fastest pace since the global financial crisis to a record $475 billion.

As the Sydney market awaits a flood of auctions in coming weeks, figures from the Reserve Bank on Friday show growth in lending to investors has hit 9.5 per cent a year, a pace not seen since March 2008.