Prime Minister Justin Trudeau is arguing that his Liberal government has been keeping its spending promises, since it came into office with a budgetary starting point of negative $18 billion.

Trudeau said Tuesday that the Liberals were consistent with their election pledge to spend about $10 billion in 2016-17, their first full year in office.

The Liberals, he added, came to power in late 2015 with a baseline budget deficit of $18 billion, even though their Conservative predecessors had predicted a balanced budget.

"We just went from a floor where the budget was balanced, because supposedly the Conservatives had balanced the budget, to what was the reality of our budget of being at about $18 billion in deficit at the end of that first year," Trudeau told a news conference.

"So, we've been consistent with our plan and our approach."

The Trudeau government has been criticized for a budgetary outlook that projects several years of deficits, including a shortfall of $23 billion for 2016-17. This year, the government is predicting a deficit of $28.5 billion, including a $3-billion accounting adjustment for risk.

Trudeau maintained that he's focused on making investments to lift the economy and vowed to remain fiscally responsible when it comes to spending.

The prime minister refused once again, however, to say when the books would be balanced. The latest federal budget does not project when the deficit would be eliminated and predicts shortfalls across its outlook until 2021-22.

"We made the decision ... in the last election that instead of focusing on balancing the books arbitrarily, and at all costs, we would focus on the investments needed to grow the economy," he said, referring to the Liberal plan to run deficits in order to invest billions in areas like infrastructure.

The Liberals won the election with a pledge to run annual shortfalls of no more than $10 billion over the first three years of their mandate and to eliminate the deficit by 2019-20.