The Canadian Federation of Independent Business says MasterCard is increasing the assessment fee it charges small businesses for using its credit cards by 20 per cent.
The move follows a similar increase imposed in the fall by Visa Canada.
CFIB president and CEO Dan Kelly says he is disappointed that the fees keep rising as small merchants struggle with an uncertain economy.
NDP consumer affairs critic Glenn Thibeault says there is no good reason for the fee hike.
Thibeault says Visa told him in November that it was increasing fees to match hikes made by MasterCard, and now MasterCard is doing the same thing.
He says it seems like Canadian small businesses are caught in the middle of a race to set higher fees.
The Competition Bureau tribunal heard last May that those fees already add up to about $5 billion annually and are the second highest in the world behind those charged in the United States.
The tribunal is expected to rule within days on whether Visa and MasterCard are engaging in anti-competitive behaviour.