MONCTON, N.B. -- Justin Trudeau is promising to do more to boost incomes for seniors, widows and widowers, one of a number of big ticket election promises he's made in the first week of the campaign.

But so far, independent costings of Liberal platform pledges by the parliamentary budget officer have not been released -- nor will they be until after they have all been publicly announced, the Liberal leader said.

A re-elected Liberal government would increase old age security by 10 per cent once a senior turns 75, and boost the Canada Pension Plan survivor benefit by 25 per cent, Trudeau pledged Wednesday morning at a lawn-bowling club in Fredericton -- a riding the Liberals picked up in 2015 as part of their sweep of the Atlantic provinces.

"Our parents have worked so hard and sacrificed so much to give us a good life," Trudeau said.

"Once they get to retirement, they shouldn't have to worry about their savings running out."

Survivor benefits would see an increase of up to $2,080 under the Liberal proposal, which would need provincial approval. Increases to OAS would mean $729 more each year for eligible seniors, with changes to take effect in July 2020 and indexed to keep up with inflation.

The Liberals say the increase to OAS, which is paid out of current government funds, would cost $1.63 billion in 2020-21, rising to $2.56 billion in 2023-24.

So far, using the Liberals' figures, Trudeau has made more than $4 billion in election promises since the campaign began one week ago, counting pledges to increase spending or reduce taxes. Nearly five weeks remain until voting day on Oct. 21.

The party is working with the parliamentary budget office (PBO) on costing elements of its platform, but those details will not be released until all campaign announcements have been made, the Liberals say. This despite the fact the Parliament of Canada Act says all cost estimates prepared by the budget office on election promises are supposed to be published "as they are announced by parties," according to the PBO website.

The Liberal campaign team says they are holding back their PBO numbers because each spending measure can affect others, which could lead to confusion. They point to a tweet from parliamentary budget officer Yves Giroux saying his office had to prepare new estimates of the effects of Conservative pledges on maternity-leave and public-transit tax credits after the Tories made a subsequent broader promise to reduce income taxes.

Not to worry, Trudeau said in Fredericton -- detailed numbers will be released eventually on "elements" of the Liberal platform.

Only the Liberal party's "big ticket items" and more complex proposals will be costed by the PBO -- something the Liberals say is how the process was always supposed to work when they legislated changes to give the PBO a mandate to estimate the campaign promises of political parties.

"I can assure you we have been and are working with the parliamentary budget officer on costing elements of our platform," Trudeau told reporters Wednesday.

"We will be releasing a fully costed, fully responsible platform in the coming weeks, including all the work done by the parliamentary budget officer on specific measures."

Through the early stage of the campaign, the Liberals -- and other parties -- have targeted their money measures at young families, but voters over 65 are often those who most reliably show up at the polls.

And, as new data shows, they are a growing demographic.

Populations estimated published Tuesday by Statistics Canada said that in all the scenarios the statistics office looked at, the proportion of people 65 and older in Canada will rapidly grow over the next two decades. By 2068, seniors are projected to be between 21.4 per cent and 29.5 per cent of the population, compared to 17.2 per cent in 2018.

Canadians will also continue to live longer, Statistics Canada said, predicting that the number of Canadians over 80 would go from 1.6 million in 2018 to 5.5 million by 2068. The fastest growing age group? Centenarians, the projections suggest.

Trudeau spent his day courting those elder voters as he made his way through New Brunswick. At a whistle stop in Moncton, the Liberal leader adeptly made his way through the Faubourg du Mascaret senior's home, shaking hands and making small talk with residents.

As he circled the room, a few musicians played some traditional French songs and at one point, Trudeau bounded over to the microphone and sang along, much to the delight of the residents.

When he told them about his promise to boost OAS, a number of people clapped and threw their fists in the air in celebration. He also thanked them for their work and contributions to the country.

"I want to recognize that society needs to care for its elders and that's what we're doing," Trudeau told them.

He was scheduled to wrap up his day at a small rally in Truro, N.S., for Lenore Zann, the Liberal candidate for Cumberland--Colchester, which the Liberals are hoping to hold after the riding's popular MP, Bill Casey, decided not to re-offer this election.

This report by The Canadian Press was first published Sept. 18, 2019

And the Liberal campaign promise recipients today are...seniors! A $729 annual bump to Old Age Security after age 75. And widows/widowers with a 25 per cent boost of CPP/QPP survivors benefits (max: another $2,080). pic.twitter.com/BkXaIR7MhC — Glen McGregor (@glen_mcgregor) September 18, 2019