WASHINGTON (AP) -- The nation's governors are asking Congress to help states recover an estimated $20 billion in sales taxes that go uncollected by out-of-state online merchants every year.

Tennessee Gov. Bill Haslam told the House Judiciary Committee on Tuesday that it isn't fair to local businesses to exempt online purchases from state sales taxes. Haslam said affordable computer software now makes it easy for even the smallest merchants to collect and forward sales taxes.

Other Republican governors, such as Chris Christie of New Jersey, have endorsed a bill to make out-of-state Internet merchants charge and collect state taxes.

Steve DelBianco, executive director of NetChoice, a coalition of e-commerce companies, said the bill does not simplify the process of collecting and distributing taxes enough to avoid imposing a burden on small businesses.