More than 9,000 covert surveillance operations were mounted by local councils over the last three years under powers designed to combat terrorism and serious crime.
The laws were used to catch dog owners whose pets fouled the streets and to investigate breaches of the smoking ban, according to data obtained by Big Brother Watch .
Across 345 local authorities across the UK, operations under the Regulation of Investigatory Powers Act 2000 (Ripa) were conducted 9,607 times between 2008 and 2011.
This works out at more than eight operations every day.
The latest figures, obtained under Freedom of Information laws, revealed Suffolk County Council had even used the powers to monitor dating agencies.
Stockton Borough Council was said to have used them to investigate a fraudulent escort agency and the movement of pigs.
And councils used the Act 550 times to try and catch fly-tippers.
Big Brother Watch said the report , which took months to compile, showed the need for a comprehensive overhaul of the system.
"The legislative framework of surveillance does not offer proper safeguards against abuse or transparency," it said.
"It is absurd that the regulation of the test purchase of a puppy falls under the same legislation that governs when security services can intercept communications."
The Local Government Association (LGA) insisted councils used Ripa "sparingly and responsibly" to combat crimes of public concern.
Mehboob Khan, chairman of the LGA's safer and stronger communities board, also stressed that from November councils will have to seek approval from a magistrate each time the Act is used.
But the report said the use of Ripa by local authorities was only the "tip of the iceberg", with a wide range of public authorities entitled to use the surveillance powers.
It asked 235 public authorities about its use of the Act. Of those, 13 - including the Scottish Environment Protection Agency - confirmed they had used it.
Six - Ofsted, the Royal Mail, the Office of Fair Trading, the UK Border Agency, UK Trade and Investment and HM Prison Service - refused to say whether they used the powers
The BBC confirmed TV Licensing did use Ripa to catch people who do not pay up but refused to give any further details due to the risk it could prejudice enforcement.
Local Government Secretary Eric Pickles said the public was entitled to know how such powers were being used.
"For public bodies, funded by and working for the taxpayer, to be using Ripa yet so vociferously trying to avoid accountability is simply unacceptable," he said in a foreword to the report.
"It is important that the public can have faith that surveillance powers are being used only in those situations where serious crimes are taking place and when there are no less intrusive alternative routes of investigation."
A Home Office spokesman said: "The use of Ripa is subject to oversight by independent commissioners and we will continue to work with them and organisations using Ripa to make clear it should only be used when necessary and proportionately."
