OTTAWA -- A Conservative plan to amend the federal anti-terrorism bill hasn't squelched opposition to the sweeping security legislation.

A handful of proposed government amendments, to be presented Tuesday, haven't alleviated Green party Leader Elizabeth May's concerns about what she calls a dangerous and undemocratic bill.

May said she plans to present five dozen amendments when the House of Commons public safety committee begins examining the 62-page bill clause-by-clause.

Seven leading human rights groups, including Amnesty International Canada and the Canadian Civil Liberties Association, issued a joint statement Monday calling on the government to withdraw the legislation.

The NDP and Liberals have also called for changes to protect civil liberties and improve oversight of security agencies.

However, Conservative ministers appearing before a Senate committee Monday made it clear the government has no plans to create a full-fledged national security committee of parliamentarians like the ones in Britain and the United States.

The government bill, drafted in response to the murders of two Canadian soldiers last October, would give the Canadian Security Intelligence Service more power to thwart suspected terrorist plots -- not just gather information about them.

It would allow CSIS to violate the Charter of Rights and Freedoms with a judge's permission, expand the sharing of federal security information, broaden no-fly list powers and create a new criminal offence of encouraging someone to carry out a terrorism attack.

In addition, the bill would make it easier for the RCMP to obtain a peace bond to restrict the movements of suspects and extend the amount of time they can be kept in preventative detention.

Sources have told The Canadian Press the government plans to introduce four changes to clarify or curtail elements of the bill, including an assurance the information-sharing powers do not apply to protesters who demonstrate outside the letter of the law.

But the amendments do not remedy several key concerns of opposition MPs and rights advocates.

"The reality is this bill will make us less safe," May told a news conference.

She denounced the legislation as vague, badly drafted and, ultimately, "dangerous garbage."

The NDP and Greens plan to vote against it, while the Liberals intend to support the bill despite their desire to see changes.

"I still hope the bill can be defeated," May said.

A Senate committee began a pre-study of the bill Monday, even though it has not yet cleared the House of Commons -- hearing from Public Safety Minister Steven Blaney and Justice Minister Peter MacKay.

Liberal Sen. Colin Kenny reminded MacKay that he once supported the idea of a committee of security-cleared parliamentarians, who would be entrusted with secret material, as a means of better monitoring spies.

MacKay said his thinking had evolved on the issue, particularly with regard to the danger of leaks.

"For matters of national security, I am concerned about the handling of sensitive information that could literally put a person's life at risk."

MacKay and Blaney praised the Security Intelligence Review Committee, a civilian body that reports to Parliament on CSIS's activities.

Michael Doucet, executive director of the review committee, recently told the senators that the watchdog would see a smaller slice of CSIS's activities in coming years.

Doucet said earlier this month his agency's annual budget has essentially been flat over the last number of years at about $3 million.

The agency has enough resources to handle complaints about CSIS, certify the spy service's annual report to the public safety minister, and carry out seven or eight reviews of various issues, he said.

However, Doucet asked whether that would be sufficient to "cover the waterfront" of CSIS's activities as the spy agency does more.