Conservative Leader Stephen Harper used a Sunday campaign stop in eastern Ontario to announce a new tax break for people who belong to service clubs such as the Royal Canadian Legion, Knights of Columbus and the Kiwanis.

Harper said the new measure would allow people to claim their service club membership fees as a charitable donations tax credit, and give them a 15- to 29-per-cent break on their membership fee.

"We're quite frank, it's not a tonne of money here, but I think it is an important recognition for the good work that many, many people do. They dedicate hours that in many, many ways really enrich our communities," Harper said.

The Conservatives estimate as many as one million people could benefit from the measure.

Before the announcement, Harper and his wife, Laureen, stopped at a food bank where the local Knights of Columbus help to stock shelves.

The Conservatives have held the area riding of Glengarry-Prescott-Russell since 2006.

With the fraud trial of Mike Duffy due to resume on Monday, Harper was also questioned on events surrounding the $90,000 payment his now-former chief of staff made to cover the senator's disputed expenses.

Questions about the trial have been a staple of Harper's brief daily question-and-answer sessions with the media for much of the past two weeks.

Asked whether his current chief of staff, Ray Novak, knew about the deal to repay Duffy's expenses and if Novak told Harper about it, Harper said: "I think that you know the answer to this question. I'm not going to comment on testimony before the courts," Harper said.

"Mr. Novak has been very clear with me," Harper continued. "The fact of the matter is this, in my view, there are two people responsible. Mr. Duffy, who is the only one on trial who took money. [In] my judgment, he should not have taken it, should have paid it back, did not do so."

"Instead, Mr. Wright did that for him, and I grant that he paid back the taxpayers, but he did so without my knowledge and without my agreement. And these were his actions, he was the boss and he is fully responsible for them," he said.

The question drew some heckling from some members of the audience, but Harper signalled them to be quiet.

Later Sunday afternoon, Harper attended a small rally in Saint-Hyacinthe, Que., where he encouraged voters to stop sending opposition MPs to Ottawa.

"I've been watching this for 22 years now, Quebecers send first big caucuses of the Bloc Québécois, now big caucuses of the NDP. Each one more useless than the one before," Harper told a crowd of about 100 supporters.

"Only Conservative MPs have actually delivered for this province," he added.

The riding of Saint-Hyacinthe-Bagot is currently held by the NDP. But the incumbent MP, elected in the 2011 orange wave, is not running again.

The riding is also near Quebec City, the region where the Conservatives are seen as the strongest in the province. The party lost ground here in the 2011 election and is hoping to gain some back.

Neither NDP Leader Tom Mulcair nor Liberal Leader Justin Trudeau had events planned for Sunday.

Bloc Québécois Leader Gilles Duceppe's campaign took him to eastern Quebec while Green Party Leader Elizabeth May is campaigning in the Victoria area.