Consumer watchdog Which? has expressed concern over the broadband marketing guidelines published by the Advertising Standards Authority last week.
Following a lengthy investigation into advertising practices within the sector, the regulator announced new restrictions on marketing practices.
Broadband providers will no longer be able to promote a headline download speed unless at least ten per cent of consumers are physically capable of achieving it.
A number of factors determine the download speeds accessible to individual customers, including distance from the local telephone exchange and line quality.
But Which? spokesperson Richard Lloyd said the ASA should have gone further with its broadband advertising restrictions.
"Advertising campaigns can now be based on the experience of a privileged few," he noted.
"If just one in ten customers get access to the top speeds advertised, that's within the guidelines."
He claimed that broadband customers have been given the green light to mislead consumers - a situation which should not have been allowed to arise.
Mr Lloyd also argued that the ASA's clampdown on 'unlimited' usage allowance claims does not go far enough.
"Unlimited' should mean unlimited at your normal broadband speed, but broadband providers will be allowed to slow down a supposedly 'unlimited' connection once a customer goes over a certain threshold," he explained.
He claimed that Ofcom should step in where the advertising regulators have failed, and make sure consumers cannot be misled about the broadband service they're paying for.
Mr Lloyd said the average speed range experienced by most customers should be clearly stated alongside the top speeds available on any broadband adverts.
At the same time, broadband packages that can be restricted should not be described as unlimited, he added.