Sheriffs in the US are pressuring Google to turn off a feature on its Waze traffic software that warns drivers when police are nearby.
They say one of the technology industry's most popular mobile apps could put officers' lives in danger.
Waze, which Google purchased for $US966 million ($A1.23 billion) in 2013, is a combination of GPS navigation and social networking.
Fifty million users in 200 countries turn to the free service for real-time traffic guidance and warnings about nearby congestion, car accidents, speed traps or traffic cameras, construction zones, stalled vehicles or unsafe weather conditions.
To Sergio Kopelev, a reserve deputy sheriff in California, Waze is also a stalking app for law enforcement.
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There are no known connections between any attack on police and Waze, but Kopelev and others are concerned it's only a matter of time. They are seeking support among law enforcement trade groups to pressure Google.
Brown and Kopelev raised concerns during the meeting of the National Sheriffs Association winter conference in Washington.
They pointed to the Instagram account of the man accused of fatally shooting two New York Police Department officers last month.
Ismaaiyl Brinsley posted a screenshot from Waze along with messages threatening police. Investigators do not believe he used Waze to ambush the officers, in part because police say Brinsley tossed his mobile phone far from where he shot the officers.
The emerging policy debate places Google again at the centre of a global debate about public safety, consumer rights and privacy.
A Waze spokeswoman, Julie Mossler, said the company works with the New York Police Department and others around the world.
"These relationships keep citizens safe, promote faster emergency response and help alleviate traffic congestion," Mossler said.
Google declined to comment.
