Companies including Google, Microsoft and AT&T have launched a campaign group calling for restrictions on the government's access to private data.
The Digital Due Process coalition says the 1986 Electronic Communications Privacy Act (ECPA) was fine at the time, but that technical developments have left it "a patchwork of confusing standards that have been interpreted inconsistently by the courts".
"1986 was a good year, but it’s time our laws catch up with how we live our lives today," says Richard Salgado, Google's senior counsel for law enforcement and information security.
The group is calling for revisions to the Act covering what they see as the most important issues - access to email and other private communications stored in the cloud, access to location information, and the use of subpoenas to obtain transactional data.
It wants warrants to be issued before internet providers and mobile carriers hand over such information to law enforcement agencies.
They say they want to "protect innocent Americans against government fishing expeditions through masses of communications data unrelated to a criminal suspect".
"Technology has changed dramatically in the last 20 years, but the law has not," said Jim Dempsey, Vice President for Public Policy at the Center for Democracy and Technology, who has led the coalition effort.
"The traditional standard for the government to search your home or office and read your mail or seize your personal papers is a judicial warrant. The law needs to be clear that the same standard applies to email and documents stored with a service provider, while at the same time be flexible enough to meet law enforcement needs."
The Electronic Frontier Foundation (EFF) has also joined the coalition - despite having had its own run-ins with Google and AT&T in the past.
"But this diverse coalition of privacy advocates and Internet companies agree on at least one thing," says EFF senior staff attorney Kevin Bankston.
"The current electronic privacy laws are woefully outdated and must be updated to provide clear privacy protections that reflect the always-on, location-enabled, Web 2.0 world of the 21st century."
Other members of the coalition include Intel, AOL, eBay and human rights groups.
The group is in discussion with the White House, FBI and the Justice and Commerce Departments about amendments to ther Act. Senator Patrick Leahy, chairman of the Senate Judiciary Committee, says he looks forward to reviewing its ideas.