The so-called secret law used to give police extra powers during the G20 summit in Toronto in 2010 is being scaled back by the Ontario government.

The Liberals came under fire for using an obscure Second World War law originally designed to protect court houses to give police authority to stop and search people during the G20.

Critics say the Public Works Protection Act was used to justify mass arrests of hundreds of G20 protesters, and the province intentionally let people believe it gave police more powers than it actually did.

The Liberals claim there was a "communications problem" with the way the law was used during the G20 summit, and refuse to offer any apology.

But they are now updating the act to limit its scope to apply only to court houses and hydro generating stations.

The opposition parties say the law was used to justify mass suspensions of civil liberties, and updating it is the Liberals' way of admitting their mistake.