In a survey of 6,000 members of ARLA, 74% of respondents said demand outstripped supply in the private rental sector, the highest level since records began.
The increase was most acute in London and the South-East, ARLA found, adding that some tenants are staying in properties for an average of 19 months as they become increasingly wary of finding a new property in a highly competitive market.
Tim Hyatt, president of ARLA, said: “The UK cannot rely on the rental sector to support the housing market in perpetuity.
“The reality is that there is a limited amount of rental property and, unless both housing supply and mortgage availability improves, renters will find that their options in the market are reduced.”
Last week, research from homeless charity Shelter showed that families faced “unaffordable private rents” in 55% of local authorities in England.
In most areas, typical rents from private landlords were more than a third of the average take-home pay.
The charity, which has called on the government to link private rents with average earnings, said, from 1997 to 2007, rents increased at one-and-a-half times the rate of incomes.
