NDP Leader Jagmeet Singh spent a third consecutive day campaigning in the critical battleground of British Columbia -- this time on Vancouver Island where his party is trying to prevent a surge by the Greens.

Singh's pitch added detail to the New Democrats' plan for housing affordability. If elected, he pledged to offer annual subsidies of up to $5,000 as way to deliver immediate help for families struggling to pay their rents.

He repeated that a New Democrat government would build half-a-million new affordable houses across the country over the next decade. But he said that since people need help right away, the NDP would subsidize rent for nearly 500,000 families.

"This will make the difference for families that are unable to pay their bills, for families that are making a tough choice between do they pay for their groceries or do they pay rent," Singh told reporters at a construction site in Campbell River, a city of about 35,000 people on the island's east coast.

"These are difficult choices that families are making -- far too difficult for far too many families -- and we'll put an end to that."

Singh warned of a "massive" housing crisis across Canada, not only in big cities but smaller communities like Campbell River.

Roughly one-third of households, or 4.7 million, are renters and the New Democrats say one-fifth of Canadians spend more than half of their incomes on rent and utilities.

The NDP said the rental benefit would cost the federal treasury $1.35 billion a year and would require another $450 million from the provinces beginning next year.

So far, political parties have been trying to win over voters by piling up promises they insist will make life more affordable. Candidates have focused, in particular, on housing and home ownership.

During his tour of B.C., Singh has been pitching the NDP's housing affordability promises, a package that includes measures designed to address concerns specific to the province.

Vancouver Island is especially important for the NDP, which won six of the area's seven seats in 2015. Green Leader Elizabeth May won the other riding. But earlier this year, the Greens wrestled away another seat on the island -- Nanaimo-Ladysmith -- in a byelection.

At a stop later Thursday, Singh was asked what his message is to island voters when it comes to why they should choose the NDP over the Greens.

"I say that it's us, the New Democrats, who have the most-coherent and most-complete plan," he said in French following a roundtable in Courtenay.

He said the NDP knows there is a climate crisis and that it shares this view with the Greens. But beyond that, he argues the NDP's proposals will address housing and health challenges -- and he insists his party has the courage to follow through on big vows like pharmacare.

Singh also said he tells voters that the NDP would ensure big corporations no longer have too much influence on the government.

The NDP leader will maintain a presence Friday on the island, with plans to participate in a climate march in Victoria.

In its platform, the NDP says it would build 500,000 quality, affordable housing units over the next 10 years -- and it promises half of them will be constructed within five years. To get it done, the party intends to work with provinces and municipalities.

The plan, the NDP says, will begin with $5 billion in additional federal funding in the first 18 months. The effort will help create thousands of jobs across the country, the platform says.

Under the Liberals, the federal government introduced a 10-year national housing strategy. A report earlier this year from the parliamentary budget officer said the strategy would result in 150,000 new affordable units, modernize 300,000 existing units and protect 385,000 community housing units.

Included in the strategy is a rental benefit launching next year that is similar to what Singh proposed Thursday. It would be attached to a household, rather than a social-housing unit, so a family could carry the benefit into the private housing market.

The budget officer estimated its average value at $3,000, below the average benefit proposed by the NDP. The supplement would cover 300,000 households once spending fully ramps up in eight years, and require provinces to match federal spending.

An NDP spokeswoman said the party would ask provinces that have already agreed to put money toward the new rental benefit to simply spend the $450 million next year, rather than waiting until 2027. Federal spending would also hit $1.35 billion next year on the benefit, instead of the $88 million estimated by the parliamentary budget office for the Liberal plan.

This report by The Canadian Press was first published Sept. 26, 2019.