The use of surveillance powers by council chiefs in Walsall more than halved within 12 months, figures have revealed.
Spying operations can be undertaken by authorities to catch out fraudsters, fly-tippers and dodgy dealers.
The use of Regulation of Investigatory Powers – RIPA – by Walsall Council came under fire from campaigners last year who claimed the powers can be open to abuse.
Between April 2011 and March 2012 there were 67 occasions they were adopted by officers in Walsall.
However, this dropped to 31 times in the last financial year, according to statistics presented to members of the Audit Committee.
It emerged last year that Walsall Council has been the biggest user of spy powers in the Black Country and Staffordshire since 2008.
Bosses have always insisted the powers are not used lightly.
They say surveillance is a key tool in helping prevent or detect crime and disorder and is only used when absolutely necessary.
Between April 2012 and March 2013 they were used four times for housing benefit and council tax investigations and nine times for anti-social enforcement.
There were 18 occasions such powers were needed in trading standards probes which can include test purchasing for knives, cigarettes, alcohol or fireworks.
This also covers investigations over taxis plying for hire, counterfeit goods, fly tipping or litter enforcement.
Big Brother Watch has previously called for a clampdown on its use, saying that the powers can be open to abuse.
An inspection by the Office of the Surveillance Commissioner and the way in which the council uses such power was carried out in spring.
Jamie Morris, executive director for neighbourhood services at the council, said: “The inspection concluded that the council was operating an efficient system for using covert surveillance.
“Material obtained through covert surveillance may be used as evidence in criminal proceedings.”
The spy techniques can be used in investigating dumped rubbish.
Hundreds of fly-tipping investigations were launched by council chiefs as part of a crackdown on rubbish dumped in the borough in 2012/13.
Three people were prosecuted and two fixed penalties issued in the drive to clear dropped waste causing an eyesore across Walsall.
The 442 investigations were conducted between last April and this March.