The NDP is asking a House committee to study the impact of tariff increases included in this year's budget, including what's come to be known as the iPod tax.

Consumer affairs critic Glenn Thibeault, who sits on the industry committee, sent a letter today to committee chair David Sweet calling for the study.

The study would look at "the increased taxation of hundreds of consumer goods detailed in Budget 2013, including the 5 per cent tax increase on iPods and MP3 players, the possibility that TVs and other goods may have been taxed retroactively, and the impact of these tax changes for consumers, retailers, and industry, and that the committee reports its finding back to the House."

The motion is expected to be discussed Thursday, but isn't likely to pass, with government MPs outnumbering opposition MPs.

The question of whether Canadians will see the cost of their MP3 players go up has been fiercely fought over between the NDP and the Conservatives.

Two years ago, the Conservatives accused the NDP of wanting to implement an iPod tax when the party called for a $5 levy on recording devices, which would have gone to artist funding. The campaign involved press conferences at music stores and was the subject of Conservative attacks on the NDP during the 2011 election campaign.

The Conservative government vehemently denies its tariff increases will apply to iPods, pointing to an exemption for devices that are in continuous use with computers. But it's not clear that exemption applies, both because importers need to present end-user certificates, presumably from the consumer who eventually buys the device, and because MP3 players like iPods are meant to be used away from the computer.

'Get to the bottom' of debate

An executive at Sony Canada has said there are too many hoops to jump through to qualify for the exemption.

Sony Canada logistics director Mark Trylinski also told The Canadian Press that the Canada Border Services Agency wrote to him last November indicating Sony would be required to pay what amounts to back taxes on previously imported televisions and "also any other goods that have been accounted under [the tariff] and for which no certificate or other record signed by the user of the commercial goods are available."

Thibeault wants to call Trylinski as a witness, as well as Western University professor Mike Moffatt, who first discovered the possibility that the cost of iPods could go up.

He also wants to hear from officials from Canada Post and the Canada Border Services Agency, as well as representatives from Apple Canada Inc.

"The study should get to the bottom of the ongoing debate regarding the taxation and/or registry system on iPods and other MP3 players," Thibeault said in his letter to Sweet.

The NDP aren't the only party taking aim at the tariff increases.

Liberal Leader Justin Trudeau has also raised the issue in question period, demanding the Conservatives cancel the increase, which is planned to take effect in 2015.

"This government's budget is imposing a new tax of over $300 million a year on goods ranging from scissors to wigs to coffeemakers," Trudeau said in question period.

"Will the government admit that this is indeed a new tax on middle-class Canadians and commit to cancel it?"

Canadian Heritage Minister James Moore said the Conservatives have cut taxes since they took office, leaving the average family of four with $3,200 more than they had under the Liberals.

"If, of course, we were raising taxes, the Liberals would be all for it ...Time and again we have lowered taxes for Canadians, time and again the Liberals have rejected it," he said.

With files from The Canadian Press