Some of the biggest High Street names have written to London mayor Boris Johnson to tell him they are unhappy with his response to the recession.
In last month's letter, 19 executives from retailers, hotel chains and other businesses called on him to do more to promote London both at home and abroad.
But the mayor said he did not want to "spend taxpayers' money prematurely".
Stores including Selfridges and Harrods signed the letter, which was sent by business organisation London First.
Both companies, as well as other signatories including Fortnum & Mason, John Lewis Partnership, Marks & Spencer and the Westfield shopping centre, are members of the organisation.
The letter, which has been seen by BBC London, reveals the companies want the mayor to address two specific issues.
They are keen for him to spend money on marketing London to overseas visitors, "seizing the opportunity afforded by a competitive exchange rate", to increase consumer confidence and boost High Street spending.
The companies also believe there has been an inadequate response to their calls for a London-wide promotional campaign which "engenders a 'wow' factor, to create a new buzz".
Des Gunewardena, chair of London First, told BBC London: "It's very important to market London overseas and it's a great time to do that because of the exchange rate.
"But London also needs to be marketed to Londoners and to people in the Home Counties who are a bit closer to us, to remind people of what a great city it is, great restaurants, shops, movies, music venues, museums."
Mr Johnson said: "The interesting thing is deciding when the moment is to push out your campaign.
"We don't want to spend a lot of taxpayers' money prematurely.
"We want to wait and decide when is the moment of optimum impact."
The companies said they raised the issue of the promotion of London in December and had hoped to see greater progress.