House prices rose 0.8% in the past month to an average of £370,759, according to Rightmove data released overnight.
The month of September is usually positive for house prices, but the researchers noted that the year’s increase is double the long-term average amidst a rise in activity levels in the market.
Numbers of new sellers were up 14% on a year ago, and the number of agreed sales rose 27%, compared to what was a subdued market last year as homeowners reacted to interest rates no longer being near zero.
However, Rightmove did note some lingering caution, with an average of 60 days for a seller to find a buyer, three days longer than a year ago.
"The autumn action has started early with a strong rebound in activity from both buyers and sellers compared to the subdued market at this time last year, continuing the momentum from the better-than-expected summer market," said Tim Bannister, Rightmove's director of property science.
He said the added "certainty" following the change of government followed by the first Bank Rate cut in four years has invigorated the market.
"Some of this will be pent-up demand from those who had to hit the pause button until now. However, windows of opportunity tend to need a momentum of good news to stay open, and there are still uncertainties ahead which could cause some of the current market activity to ease," he said.
Mortgage trackers show the average five-year fixed rate is now 4.67%, down from a peak of 6.11% in July last year but still nearly double the 2.34% three years ago.
There is a Bank of England meeting on Thursday this week, where no rate cut is expected, while many economists expect a cut in one or both of the following meetings in November and December.