WINDSOR, Ont. - U.S. Transportation Secretary Ray LaHood calls Canada's offer to pay up to US$550 million for the U.S. side of a proposed Windsor-Detroit bridge "quite extraordinary."

LaHood said Monday in Washington that he is waiting to see if the Michigan Legislature will vote to allow the state to get involved with the $5.3 billion project.

The state House could vote as early as this week on legislation that would permit Michigan's transportation department to enter into a relationship with Canada and a private project developer.

Michigan legislators face a June 1st deadline to approve bills allowing Michigan to join the new project.

Transport and Infrastructure Minister John Baird travelled to Detroit last week to present Canada's offer to lend the financially strapped state more than half a billion dollars to speed up construction.

The proposed span over the Detroit River is opposed by owners of the nearby Ambassador Bridge, who want to expand their own crossing.

Detroit International Bridge Co. has vowed to sue Canada under NAFTA, claiming Canada is trying to undermine it by coercing Michigan into building a new, competing span.

The company has said a new span would siphon off traffic from the Ambassador Bridge and bankrupt the firm.

It also disputes Ottawa's prediction that truck traffic will triple, and vehicle traffic more than double within 30 years.

The Canadian government says 8,000 trucks and 68,000 travellers cross at the Windsor-Detroit border point daily, along with $130 billion a year in trade.

The project to build a second bridge is expected to create 10,000 construction jobs over five years and 25,000 permanent jobs once it is complete.

The current automotive links between Windsor and Detroit -- a tunnel and the bridge -- together constitute the busiest international border crossing in North America by trade volume.

More than a quarter of all merchandise trade between the United States and Canada crosses the Ambassador Bridge alone.

With files from The Associated Press