Rural campaigners are calling for an end to the spread of advertising in roadside fields, saying they deface the countryside and threaten safety.
The CPRE said the ads can prove a distraction to motorists
The Campaign to Protect Rural England (CPRE) said it should be made a legal duty of local authorities to enforce planning permission regulations.
But the Office of the Deputy Prime Minister said that was unnecessary.
It said it was working on regulations on controlling outdoor adverts and will be reminding councils of their powers.
Some farmers who have hired out their fields for advertisements said they were only following the government's advice to find more diverse sources of income.
The CPRE said many types of roadside advertising were authorised by regulations - but these were predominantly located in urban areas.
In a survey, it counted nearly 900 billboards on major routes in the countryside across England - an average of one every three miles.
These advertisements were either placed on trailers in fields or were on hoardings alongside roads, the CPRE said.
The group said it believed many of the advertisements had been set up without the necessary regulatory consent.
"For more than 50 years, planning controls have saved the English landscape from the pox of outdoor advertising," said Paul Miner, the CPRE's planning campaigner.
"This achievement is now in danger. Billboards and hoardings are mushrooming alongside motorways and major roads across England, despite government policy and regulations clearly stating they should be strictly controlled."
In a statement, the Office of the Deputy Prime Minister said: "We do not agree with the CPRE's call for a legal duty to enforce advertisement controls as it is often sufficient to get the advertisement removed by alerting the landowner to the penalties for displaying an unlawful advertisement.
"In July the Office of the Deputy Prime Minister wrote to all local planning authorities to remind them of their powers to deal with advertisements in fields alongside motorways and trunk roads.
"In addition we are currently working on new regulations to control outdoor advertising and intend to consult on them later this year, along with revised and updated guidance to remind local planning authorities of their powers to remove illegal advertisements."