Kingston Council could be losing out on £400,000-a-year in rent by not letting out hundreds of its garages, it has been claimed.
A residents' scrutiny panel (Krisp) said the council had "no clear or cohesive plan to manage" its 1,234 garages, of which 474 were rented out, meaning service to residents was "poor" and income less than half what it could be.
A garages manager should be appointed to oversee the stock and rake in more cash, including through advertising, a Krisp investigation panel said.
It added: "Applicants wishing to rent garages experience a poor and disinterested level of service.
"Across all the estates in the borough there was little maintenance being carried out to the garages plus there was a great deal of confusion around policy and areas of responsibility."
The council currently recieves £304,000 a year in garage rent.
Conservative lead member for housing Councillor Ian George said: "It's a lot of money and we obviously need the money. I can assure you we will be looking at it and we will be taking residents' comments seriously."
His opposite number, former lead member Councillor Patricia Bamford, said: "The £400,000 is hugely optimistic because some of the properties they're talking about would be affected by the programme to free up more sites and build affordable homes.
"I would like to say that I agree with the recommendations that they have made. [A garages manager] would pay for itself in no time at all."
Garage reform under the deposed Liberal Democrat administration, in power for 12 years, suffered from time constraints and competition with other policies, she added.
Neighbouring Sutton Council was used as a benchmark by the investigators, who said it earned £500,000 a year by letting 76 per cent of its 1,200 garages, having previously suffered similar problems to Kingston.
Lambeth earns £1m a year from its stock.