Remember when the federal Liberals axed the tax break for Canadians who take public transit? There may be more of that coming in the next federal budget, according to tax experts.

READ MORE: Federal Budget 2017: How the budget will affect your pocketbook

The government may be under pressure to find new revenue without raising taxes, and eliminating tax credits would be one way to do so, said Jamie Golombek, managing director of tax and estate planning with CIBC in Toronto.

Prime Minister Justin Trudeau’s pledge to peg the Canada Child Benefit (CCB) to inflation starting this year is one thing that may require Ottawa to find new sources of funding, said Lana Paton, managing partner of PwC Canada’s Tax Services.

READ MORE: Indexing Canada Child Benefit to inflation would cost extra $5.8B by 2026, watchdog says

Indexing the CCB to the cost of living will provide an additional $5.6 billion over a four-year period in support of families with children under 18 years of age, the government said. And that money will have to come from somewhere.

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The Liberals have “already increased taxes dramatically on the top one per cent,” Golombek said. And their agenda is to reduce taxes on middle-income Canadians.

The government has also outlined a series of measures to tighten the tax rules for small business owners and professionals who operate as incorporated small businesses, such as lawyers and doctors.

So what else is left to raise more money?

WATCH: Public transit tax credit removed from federal budget

2:03 Public transit tax credit removed from federal budget Public transit tax credit removed from federal budget

“One thing they’ve been looking at for a couple of years now is the whole personal tax system, where there’s a variety of these so-called ’boutique tax credits,'” Golombek said.

Tax credits lower the potential revenue that the government would be able to collect by allowing certain taxpayers to subtract a certain amount of money from the taxes they would otherwise owe. The government uses tax credits to encourage people to behave in certain desirable ways, for example, to take public transportation rather than drive a car.

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READ MORE: Canada Child Benefit should increase with inflation, anti-poverty group says

But these and other tax breaks can be a significant drag on public coffers. The combined value of these measures was nearly $118 billion in 2015, equal to over half of the money the government gets from personal and corporate income taxes and the Goods and Services Tax (GST), according to a comprehensive review ordered by the Trudeau government.

In addition to the public transit tax credit, the Liberals have eliminated tax breaks for things like the cost of textbooks and children’s arts and fitness classes. But there are dozens of other things for which Canadians can claim a discount on their tax returns, such as the volunteer firefighters’ amount (VFA), the Canada employment amount that meant to help employees with work-related expenses like uniforms and computers, and the first-time homebuyers tax credit.

READ MORE: Federal budget 2016: Trudeau eliminates Harper-era tax credits

The latter, in particular, could be a candidate for the chopping block this year, according to Paton. The credit allows Canadians who did not previously own a home to claim $5,000 for the purchase of a house.

Nixing this tax break would be another way for the government to cool an overheated housing market, Paton said.

It might be difficult for the Liberals to target other tax credits, since “a lot of [them] do benefit the middle class,” she added.

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Golombek, on the other hand, doesn’t seem a fan of tax credits, which he calls “massive subsidies for people to do something they were going to do anyway.”

A public transit tax credit, in other words, isn’t very likely to actually affect your decision to opt for, say, the bus over your car.

“The tax system should be about collecting revenue on a broad base,” he said. “If they perhaps eliminated all of the tax credits, quite frankly, they may be able to lower the tax rate for every Canadian.”