Opposition MPs lambasted the Conservative government on Monday for quietly killing an access to information registry used by journalists, experts and the public that users say helped hold the government accountable.

Amid cries of "shame" by his party members, Liberal Leader Stéphane Dion said Prime Minister Stephen Harper's Tories "took another step to limit transparency and accountability" in Ottawa by closing the Co-ordination of Access to Information Requests System, or CAIRS.

"Why did the government shut down the registry?" Dion told the House during Monday's question period. "What do they have to hide?"

But the prime minister dismissed the charge, insisting his government has widened access to information "more than ever before."

The CAIRS registry is an electronic list of nearly every access to information request filed to federal departments and agencies. It was originally used as an internal tool to keep track of requests and co-ordinate the government's response between agencies to the release of potentially sensitive information.

More recently, users have mined the database to do statistical studies, submit new requests with fine-tuned wordings and discover obscure documents — often using the resulting information against the government.

But last week, a notice to civil servants from the Treasury Board stated that retroactive to April 1, "the requirement to update CAIRS is no longer in effect."

Harper told the House on Monday that CAIRS — launched in 1989 — was expensive and a "centralized tool" created under the previous Liberal government. The Liberals only came to power in 1993.

The prime minister added it was decried by a freedom of information expert as "a product of a political system in which centralized control is an obsession."

"That's why the government got rid of it," Harper said.

Dion reminded MPs that Treasury Board officials had previously said the registry was shut down because federal departments didn't value it.

"Why would they?" he said. "Instead of them, the government should have consulted the clients who are using it every day."

'Precious tool for democracy'

During the debate, Treasury Board President Vic Toews identified the critic quoted by Harper as Alasdair Roberts, a U.S-based Canadian political scientist. Roberts is known among access-to-information researchers for having built a web version of the database by requesting CAIRS electronic records through an Access to Information Act request, and updating the site monthly.

Reached in India via e-mail by CBCNews.ca on Monday, Roberts said CAIRS was "generally acknowledged internally to be a clunky method of oversight and co-ordination," but added that the Conservatives' decision to kill it raises questions about how the government will manage access to information requests.

"How does [the Privy Council Office] communications and security and intelligence keep track of incoming requests? How do key departments keep track of sensitive requests arriving elsewhere?" wrote Roberts, now a law and public policy professor at Boston's Suffolk University.

Roberts added he doubted his criticism of the system contributed to the Tories' decision.

"Based on past experience, my views are almost certainly not the motivation for their policy change," he wrote. "The material question is whether they've abandoned the idea of oversight and co-ordination, or just found better (and maybe less visible) ways of doing it."

During Monday's Commons debate, NDP Leader Jack Layton told the House the decision to kill the registry was just the latest example of the Tories betraying their 2006 campaign pledge to bring more transparency to the federal government.

"The Canadian people are losing trust in the Conservatives and if you boil it down, it's because the Conservatives don't trust Canadians," Layton said. "Why do they keep burying their promises?"

Bloc Québécois MP Carole Lavallée called the registry "a precious tool for democracy" and called for the government to reinstate updates to the database.

But Toews insisted his government was "opening up the books."

"For the first time, Canadians can see how their tax dollars are being spent by the CBC, the Wheat Board and Canada Post," Toews told the Commons.

Also on Monday, the Canadian Association of Journalists said it is "deeply concerned by an ongoing pattern of shutting off access to information by the federal government."

"Without updates to the database, it will become only easier over time for federal departments to delay, obfuscate and potentially withhold valuable government information," the organization said in a release.

CBC journalist David McKie took over work on the web-based version of CAIRS from Roberts in 2006 using another publicly accessible website (http://www.onlinedemocracy.ca ).