OTTAWA -- And now it's $1.6 billion.

That's Ottawa's new projection for next year's budgetary surplus following Prime Minister Stephen Harper's $5.8-billion infrastructure announcement.

Canada's surplus forecast for 2015-16 is now $300 million lower than the $1.9-billion projection the Finance Department published two weeks ago in its fall fiscal update.

The government says Harper's infrastructure announcement will also lower surplus predictions by a total of $1 billion over the following four years.

The adjusted projections come a day after Harper unveiled a multibillion-dollar tableau of federal infrastructure upgrades across the country.

The Conservative government has now left even less surplus money for its political rivals to fight over in the 2015 election year.

It means less cash than opponents might have expected, due in large part to low oil prices and Ottawa's expensive new tax cuts and benefits for families with kids.

In last spring's federal budget, the government projected the 2015-16 budget to run a $6.4-billion surplus.

Harper's infrastructure announcement Monday faced criticism for containing old promises, but the Finance Department has said the majority of the cash represents new funds that had not been previously announced.

The prime minister said the government would invest in projects expected to create jobs and deliver quick results -- most of it over the next three years.

About $2.8 billion of the total was earmarked to improve historic sites, national parks and national marine conservation areas.

Ottawa says the rest of the infrastructure cash will be spent after 2019-20.