A pair of proposed changes to the federal budget put forward by opposition parties will determine whether the minority Liberal government will fall, which could trigger an election.

The government says it has informed opposition parties that two votes in the House of Commons — on a Bloc Québécois sub-amendment today and on a Conservative amendment Thursday — are considered confidence votes.

A third opportunity to pass judgment on the massive budget comes Monday, when the House votes on the main motion to approve the government's budget policy.

Prime Minister Justin Trudeau's Liberal government needs the backing of at least one of the three main opposition parties to survive a vote of confidence.

NDP Leader Jagmeet Singh has said repeatedly he plans to support the budget as a whole, but has not passed word on this week's amendments in particular.

The Conservative amendment seeks to revise the budget to ramp up vaccination rollout during the third wave of the COVID-19 pandemic to stimulate jobs and economic growth.

Bloc Leader Yves-François Blanchet tabled a sub-amendment calling for an added $28 billion this year in health-care transfer payments to the provinces and a hike in old age security benefits for all seniors, rather than just those aged 75 and above.