The national ad buy, which began airing last month, is part of some $7.2 million allotted to the Heritage department this year to promote the government's "Canada 150" campaign.
A spokesman for Heritage Minister Shelly Glover said it is important to remind Canadians of the people and events that led to Confederation, notably the Charlottetown and Quebec conferences of 1864.
"This anniversary is a key milestone on the road to 2017," Mike Storeshaw said in an email.
"These conferences were critical events in Canada's history, where the foundation was laid for Confederation and what would eventually become Canada in 1867."
He said the "government believes it is important for all Canadians to be reminded of just how significant these earlier milestones were on the road to national unity, and to honour the courage and foresight of the fathers of Confederation."
The $7-million Canada 150 ad budget makes it one of the larger campaigns among the $60.4 million in advertising the Conservative government has signed off on to date for 2014-15.
The Harper cabinet has allotted $10 million to advertise its annual "economic action plan," $8 million to promote its "better jobs" program, $5 million promoting services to veterans and $5.5 million to combat illicit drug use — a campaign that has been criticized as a partisan rebuttal to a Liberal pledge to legalize marijuana.
Earlier this summer, three national medical organizations announced they were rejecting an invitation by Health Canada to endorse the government's anti-drug campaign because they could not "support or endorse any political messaging or political advertising on this issue."
NDP critic Mathieu Ravignat said the size of the Canada 150 ad budget — this far in advance of the 2017 anniversary — raises suspicions the campaign is more pre-election positioning by a Conservative government that he says has a history of using public ad funds for partisan purposes.
"Given the past borderline partisan nature of their ads, we have to be careful about the messaging in these ads, as well as the costs," said Ravignat, noting there's still three years of Canada 150 advertising to come.
"We need to be suspicious about the timing of these ads before the election," expected no later than October 2015, he added.
The Canada 150 ads include 30-second and one-minute spots in English and French that both conclude with the tagline "Strong Proud Free" printed across the television screen.
After introducing the fathers of Confederation, the ads describe how proud those men would be of Canada today, while flashing images of Canada Day fireworks over the Parliament buildings, or Sidney Crosby celebrating his Olympic gold-medal-winning goal in Vancouver.
Alex Marland, a political science professor at Memorial University in St. John's, N.L., is currently doing research on how the brand message of governing parties gets entwined with government advertising.
He compared the current Canada 150 ads with those commissioned for the country's 125th anniversary under the Mulroney government in 1992.
"The Canada 125 ads were designed by politically correct bureaucrats; this is designed by experienced marketers," said Marland.
"It's very smart marketing because it's reinforcing other messages the government is sending out."
The ads emphasize the importance of strong leadership, highlight hockey (a Harper government touchstone) and embrace the Conservative party's history-based patriotism, but that doesn't necessarily make them propaganda, said Marland.
"Whether or not this is propaganda is kind of in the eye of the beholder," he said.
A more telling measure will be when the government chooses to pump up the advertising saturation.
"How much of this advertising will be going on in the lead-up to a federal election campaign?" asked Marland. "That would be the only thing that concerns me."
Follow @bcheadle on Twitter
Also on HuffPost