OTTAWA -- A Liberal MP's riding association has been slapped with a hefty fine for robocalls that broke the rules by anonymously attacking his Tory rival's stance on abortion during the last election campaign.

A recorded message to voters in the southern Ontario riding of Guelph violated telemarketing rules by failing to state that it came from the Liberal party or MP Frank Valeriote's campaign, the Canadian Radio-television and Telecommunications Commission said Friday.

The infraction carried a $4,900 fine.

"The violations involved a pre-recorded message sent by the association that failed to identify on whose behalf the call was made; provide necessary call-back information; and display the originating telephone number or an alternate number where the originator could be reached," the CRTC said.

The automated calls, made for about an hour on Apr. 30, 2011, warned against Conservative candidate Marty Burke's views on abortion.

"The race in Guelph is very close," said the message, recorded in a woman's voice. "Vote strategically on Monday to protect our hard-earned rights from the Conservatives and Marty's extreme views."

Valeriote won the contest by a comfortable margin.

The Guelph MP said he accepts the CRTC's findings and is sorry for breaking the rules.

"We were unaware of certain requirements and inadvertently neglected to include some identifying features in the message, such as a phone number and address," Valeriote said in a statement.

"When I first learned of the errors in the call earlier this year, I was fully and immediately co-operative with the CRTC; I take full responsibility and apologize for the infringement."

Both the riding association and Valeriote have agreed to put into a place a compliance program to ensure they don't again run afoul of the rules, the regulator said.

"We appreciate that Mr. Valeriote and the association fully co-operated with our investigation and committed to comply with the rules in future campaigns," CRTC chief compliance and enforcement officer Andrea Rosen said in a statement.

"We expect political party associations and candidates who are running for office to put appropriate safeguards in place to ensure compliance with the rules."

Allegations of fraudulent and misleading phone calls designed to suppress the vote of targeted constituents during the May 2, 2011, election are currently being investigated by Elections Canada.

The investigation has centred on Guelph, where a number of residents say they received automated phone calls from someone claiming to be from Elections Canada and directing them to a wrong or non-existent polling station.

While the misleading phone calls appeared to target non-Conservative voters, the Conservative party insists it had no involvement in any such scheme and says it is assisting the investigation.

The RCMP has been called in to help Elections Canada with its investigation.

The CRTC fine pertains only to a breach of telemarketing rules and not to any possible violation of the Canada Elections Act.

Valeriote called the incident "an important learning experience."

"Consequently, I have volunteered to do whatever I can to assist the CRTC to educate MPs, candidates and their staff to the full extent of regulations governing calls and the use of auto-diallers," Valeriote said.

"It is important for these types of investigations to take place regularly to ensure that Canadians are aware of our rules and that they are respected."

Conservative Party spokesman Fred DeLorey questioned whether the calls swayed the election result in Guelph. Valeriote defeated runner-up Burke by 6,322 votes.

"One can't help but wonder, without these misleading phone calls to voters, would the election outcome in Guelph been different?" DeLorey said in a statement.

"The Liberal party has some explaining to do -- How many other Liberal campaigns broke Canadian telecommunication rules? How many used robocalls to mislead Canadian voters?"

The CRTC fine offers just the latest evidence of electoral missteps in recent years.

In March, the Conservatives paid back Elections Canada $230,198 and dropped its Supreme Court appeal of the so-called "in-and-out" scheme.

The case involved national funds funnelled to local ridings that in turn paid for national advertising in the 2006 election -- a practice that caused the party to exceed its legal spending limits.

The party also settled last November for another $52,000 for breaking the Elections Act.

Conservative Senators Irving Gerstein and Doug Finley and party officers Mike Donison and Susan Kehoe were charged with wilfully violating the party's spending limit in the 2006 campaign.