Under current law, people who buy goods online are supposed to declare those purchases on their tax forms, but few do. As a result, most people do not pay taxes on their online purchases.
The Marketplace Fairness Act, sponsored by Sens. Dick Durbin (D-Ill.), Mike Enzi (R-Wyo.) and Lamar Alexander (R-Tenn.), would empower states to force online retailers to collect sales taxes.
In his letter, LePage insisted the bill would not raise taxes.
"It simply provides for the collection of sales tax already due," he wrote.
He said it would be "quite helpful to have certainty about our future revenue streams" as he negotiates a budget with state lawmakers.
"I have pledged to lower Maine income taxes and stop wasteful government spending," LePage wrote. "One powerful tool in achieving these goals would be to have the ability to collect taxes that are due."