Landlords should pay letting fees rather than tenants, the Citizens Advice Bureau has argued, because they are able to shop around for the cheapest deals in a way consumers cannot.
The advice service said the number of requests for help from people having problems with letting agents increased by 14% to 6,500 in the year to June 2016. Young people saw the largest rise. There were 810 cases involving those aged 17 to 24, a 125% increase.
The government's English Housing Survey shows the median letting agent fee in 2014-15 was £200 ($261), up 60% over five years. The Bureau said its research has found letting agent fees as high as £700. The Renters' Rights Bill, which would ban letting fees for tenants, is working through Parliament.
"Letting agents are hiking up their fees for a service that's often not up to scratch," said Gillian Guy, chief executive of Citizens Advice.
"With fees rising year on year for letting agents, many tenants will rightly be wondering why they are paying hundreds of pounds for a simple contract renewal or for management services that leave them waiting months for essential repairs.
"Private renters shop around for properties, not for letting agents. Landlords are better able to choose agencies based on performance and cost and it should therefore be landlords paying letting agent fees, not tenants picking up these rising costs."
But David Cox, managing director of the Association of Residential Letting Agents, said fees cover important costs such as credit searches, drafting tenancy agreements and drawing up inventories.
"All of these items cost letting agents money to carry out, and in fact, provided the agent has a fair pricing structure, the agent will not make a noticeable profit on charging for these items," Cox told the BBC.
"Landlords too, incur their own costs to the agent, for services such as advertising the property and arranging viewings, amongst others. Rather than simply transferring the total cost onto the side of the landlord, what is crucial is to provide consumer protection through better regulation of the private rented sector."