The report was based on HomeLet statistics.
Sales of new builds in London have fallen by as much as 41%, a report by London Central Portfolio (LCP) suggests.
Based on HomeLet statistics, the report highlighted a 6% discount on asking rents in south London and a 14.8% decrease in the number of properties to let in the last three months.
This slowdown in London rents reflects the first annual fall in values (1.2%) since 2009.
Naomi Heaton, chief executive of LCP, said: “In much the same way as we see in the sales market, there is increasing fragmentation in the lettings market, according to property type.
“Alongside the oversupply of rental stock in new build heartlands, the uncertain economic outlook has resulted in tighter tenant budgets.”
The number of available properties to rent around the Battersea and Nine Elms area south of the river has increased by 28.1% in the last three months compared to figures in 2016.
Prime central London however has seen a rise of 1.5% over the last three months in rents and the number of properties being let has also seen a 2.5% increase over the same period.
“In contrast to the dynamics South of the River, the mainstream rental market in PCL has continued to perform positively as demand for well-presented rental property remains high and stock remains scarce.”
