Activist groups on Wednesday unveiled a new coalition aimed at repealing the law authorizing mass surveillance by US intelligence and law enforcement agencies.

"This is our chance to end mass surveillance under the Patriot Act," said the website of the coalition Fight215.org, which wants to repeal Section 215 of the Patriot Act.

The move comes with the law set to expire on June 1, and uncertainty about whether Congress will extend those provisions or whether certain data-sweep programs would end.

The activist groups led by the Electronic Frontier Foundation are pressing lawmakers to end the programs unveiled in documents leaked by former National Security Agency contractor Edward Snowden.

"The NSA has accomplished the equivalent of sitting inside our homes, taking notes on where we go, who we talk to, and what we do during the day," said Nadia Kayyali, activist at the Electronic Frontier Foundation.

"The American public has called for a change, and 'Fight 215' is our opportunity to bring American law back in line with our constitution."

The White House said last month it would stop bulk collection after June 1 if not specifically authorized by Congress.

But many activists argue there could be other loopholes to allow mass surveillance to continue.

In March, major US technology organizations joined in a letter to top officials and lawmakers calling for surveillance reforms.

The new coalition seeks to rally public support to write and call members of Congress.

The coalition includes the American Civil Liberties Union, the Sunlight Foundation, Center for Democracy & Technology and the Council on American-Islamic Relations, among others.