Vacancy rates are set to tighten in a number of inner-city suburbs as investors offload their properties to take advantage of rapidly rising prices, amid signs apartment rental markets are stabilising.

More than one in three (34 per cent) of properties listed for sale across Leichhardt in Sydney’s inner west are ex-rental homes, the highest proportion of investment properties currently on the market in a given area, data from Suburbtrends.com shows.