Obama sent his $3.9-trillion fiscal 2015 budget to Congress on Tuesday, but it doesn't include the $250 million cost of a border inspection plaza.
The plaza is a vital part of the planned New International Trade Crossing to link Detroit and Windsor, Ont.
The Canadian government is funding most of the bridge, expected to open in 2020.
Democratic U.S. Rep. Gary Peters calls the decision not to fund the plaza a "grave oversight."
New International Trade Crossing coalition spokesman Tom Shields says the full $250 million isn't needed in one year but can be spread over several years.
Ottawa announced in its budget last month that it would spend some $631 million over the next two years to help build the new Detroit-Windsor crossing.
The commitment included $470 million in new funding, which was in addition to money already in department budgets.
Delays in crossing the border are a major headache for the auto industry, which relies on the timely delivery of parts and other supplies to keep their production lines moving.
— With files from The Canadian Press
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