Prime Minister Stephen Harper must make it clear he rejects an anti-gay slur uttered by one of his MPs if he doesn't want to see Conservative party support drop, says a pollster.

Nik Nanos, president of Nanos Research, told CTV's Question Period on Sunday that the Conservatives have retained support so far by shifting the focus away from social issues.

"Think about the last couple of years where the focus has been: On Afghanistan, the economy, a transparency in government and not a lot on social issues," he said. "That's why Canadians have been able to hold on and that's what makes (Lukiwski) a very important issue."

But the emergence of a 1991 videotape containing some nasty anti-gay slurs by Saskatchewan MP Thomas Lukiwski, then an organizer for the provincial Progressive Conservative party, has put the focus back on the social side -- at least temporarily.

"The prime minister needs to deal with this issue directly and try to put it behind him as soon as possible," Nanos said. "I think the prime minister has to personally say, 'I don't accept these comments, I repudiate them and it's not part of the party or the government or where its mind is at on a lot of these issues right now."

Harper, who has been in Europe, hasn't spoken to reporters on his tour since the story broke.

Nanos said mainstream Canadians have been uncomfortable with social conservative attitudes on issues like sexual orientation. He pointed to the troubles experienced by the Reform and Canadian Alliance parties over their stances on social issues.

Even in the 2004 federal election, for example, Ontario Conservative MP Cheryl Gallant compared abortion to the beheading of Western hostages in Iraq. She also suggested most Tories would like to see hate crimes protection rescinded for gays and lesbians. The Liberals ended up forming a minority government in that election.

In this current controversy, Lukiwski -- speaking directly to the camera -- said that gay men are "homosexual faggots with dirt on their fingernails that transmit diseases." Lukiwski was 40 years at the time.

Lukiwski was quick to apologize, telling his colleagues in the House of Commons on Friday he was "stupid, thoughtless and insensitive."

"The comments I made . . . should not be tolerated in any society," he said. "They should not be tolerated today, they should not have been tolerated in 1991, they should not have been tolerated in years previous to that."

Government House leader Peter Van Loan accepted the apology, calling it "quick, complete and unequivocal."

Nanos said Lukiwski's heartfelt and prompt apology was a good first step for the Conservatives to put this scandal behind them.

"There are two things at play -- how the member responds and what he does going forward and what the prime minister does in regards of saying definitively, 'this is not acceptable and not part of what our party believes in,'" Nanos said.

The pollster also said opposition parties won't have much ammunition if Harper reacts in that way.

"Realistically they have to wait to see what the prime minister does because that will be the first indicator to see if this is a bigger story," Nanos said.

"If the Prime Minister is not forthright and he doesn't take things head on, I think the opposition is going to pounce.  If he deals with this swiftly and directly, then there's not going to be a lot to poke at."