Advertisers' representatives are to lobby the Government in protest at plans to stop businesses cashing in on London's hosting of the 2012 Olympics.
Olympics minister Tessa Jowell is responsible for the legislation
The Olympics Bill sets out strict rules to combat use of Games-related words and images by non-official advertisers.
The Institute of Practitioners in Advertising says that will prevent most companies benefiting at all from 2012.
"This is an unreasonable bill and revisions are required," IPA legal director Marina Palomba told BBC Sport.
"It's absolutely right that official sponsors are protected, but there has to be a balance."
The bill was drawn up by the Department for Culture, Media and Sport (DCMS) to establish the legal framework for London to stage the Games.
And London's organising team insists the legislation is necessary to safeguard the investment of official sponsors.
"There is absolutely no intention of stopping London businesses from becoming involved in the Games, quite the reverse," said a London 2012 spokesman.
"There will be hundreds of opportunities across a wide range of areas and sectors for London businesses and we look forward to outlining them all over the next seven years."
The bill was published on 14 July, just eight days after London beat Paris to win hosting rights at a vote in Singapore.
Its provisions include laws to stop ambush marketing - the practice of a company associating itself with an event without being an official sponsor.
Companies can sponsor the Games through the International Olympic Committee's Olympic Partner Program, or through domestic deals with the London Organising Committee.
Existing legislation already prevents non-official sponsors from using distinctive "Olympic marks" like the Olympic rings.
But the new bill will make it illegal to combine words like "games", "medals", "gold", "2012", "sponsor" or "summer" in any form of advertising.
Breaches can be punished by fines of up to £20,000, or unlimited fines in more serious cases.
The IPA argues that this will rule out any sort of 2012 "halo effect" for businesses in the UK.
"You won't even be able to say 'come to London in 2012' because it will infringe the act," said Palomba.
"Suppose you are producing a suntan lotion, you can't say 'get bronze in London in 2012'.
PROTECTED OLYMPIC MARKS
Words 'Olympic', 'Olympiad' and 'Olympian'
Olympic rings, Team GB and British Olympic Association logo
Words 'London 2012', London's bid logo and derivatives of London2012.com
The 2012 Games logo and mascots (not designed yet)
Olympic motto Citius, Altius, Fortius/Faster, Higher, Stronger
The British Paralympic Association and team logos
Other banned words include games, medals, gold, silver, bronze, 2012, sponsor, summer
Ticket touting and sale of unofficial merchandise will be illegal
"I made submissions to the DCMS before it published the bill and it hasn't taken into consideration any of my comments at all.
"Blatant ambush marketing has to be prevented but there are already laws in existence to prevent that.
"This is new legislation which gives the event holder unparallelled power. Why should the IOC have the monopoly on the terms London, 2012, summer, gold, silver and bronze?
"London businesses in particular will be paying for these Games but they are being deprived of benefiting from them because they will basically have to pretend they are not happening."
The IOC argues that the legislation is necessary to safeguard the investment of its official sponsors.
And a DCMS spokesman said speculation on what the new rules would and would not allow was "premature", with businesses to be given two years' notice before the laws were brought in.
He added: "The idea is to protect the Olympic brand and ensure that we meet the criteria of the IOC.
"We will do that, and we won't go any further than we need to go, or any less far than we need to go."