The number of available properties in the capital's rental market is up 8%.
Asking rents outside London rose by 2.8% in the second quarter of 2017, the Rightmove Rental Trends Tracker has shown.
This is in line with the 2.7% average seen over the past five years at this time of year.
Sam Mitchell, head of lettings at Rightmove, said: “Many thought that rental supply would constrict this year, as landlords sold up and looked to invest their money elsewhere, but clearly this isn’t happening yet.
“Perhaps landlords are remortgaging their buy-to-let properties instead, as they still feel it’s a better investment than looking to other industries.
“Anyone hoping for a drop in prices due to the extra choice will be disappointed though as rents are following a very similar trend to previous years.”
The number of available properties on the rental market outside London is 7% higher than this time last year, and up 8% in the capital.
Ascot offers the best choice for renters in the south and Salford is leading the way for renting in the north.
Rental prices in London are still running lower than last year and are now 3.2% lower than their peak of £2,020 per month this time last year.
