The situation is partly fuelled by a lack of available space to build new homes, says the district council.
But big money is also snapping up properties with the rental potential to make a mint, say estate agents.
Demand and supply send Sevenoaks house prices into stratosphere
06-22-2015
MODEST HOMES, SKY HUGH PRICES: Argyle Road in Sevenoaks is one sought-after road in town
The continuing rise in prices was underlined this week after it was revealed a two-bedroom terrace house in Gordon Road had been snapped up for half a million pounds.
The National House Building Federation has also named Sevenoaks one of the most difficult places in the UK for first-time buyers to get a foot on the property ladder.
"It's among the top 20 areas where average wages, house prices and limited ability to save for a deposit collide to price out would-be homeowners," a spokesman said.
The federation calculates the district's lowest-paid workers would need to borrow around 18 times their salary to buy Sevenoaks' cheapest properties.
Estate agent Stephen Quinn, from Taylor and Tester, told the Chronicle: "Demand is outstripping supply in Sevenoaks and the competition is fierce.
"Buyers are up against the buy-to-let market. The current low interest rates mean investors can get a better return putting their money into property than leaving it in the banks.
"If you're looking at an increase in property value in excess of five per cent, you'd be hard-pushed to find a savings account to match that. You'd probably have to tie your money up for long periods in high risk bonds to get that sort of return."
Mr Quinn said investors have been known to stump up deposits of £100,000 – a sum first-time buyers just can't match.
And, with the buy-to-let market pursuing properties up to £500,000, existing homeowners looking to upgrade are also being hit.
The only property sales not coping well in the current climate are those of the multi-million-pound mansions.
Philip James, from estate agents Strutt and Parker, said: "That part of the market is moribund at present – stamp duty is killing it.
"But elsewhere, properties around Montreal Park – Marlborough Crescent and Lyndhurst Drive, for instance – are defying gravity at the moment.
"You'll also find that anything within walking distance of the station – St Botolph's Road and The Drive, for instance – will do well."
Sevenoaks District Council, which joined forces with housing association Moat on Monday to launch the second tranche of a programme to help people buy on the open market, said a lot of land is off limits for house building.
"With 93 per cent Green Belt, 60 per cent Area of Outstanding Natural Beauty, and land and property values amongst the most expensive in the UK, delivering affordable housing in Sevenoaks District is an increasingly challenging task," said a council spokesman.