The Montana House bill, introduced by Democratic Rep. Betsy Hands of Missoula, is being considered by the Senate Agriculture Committee. The measure has already passed the House on a 57-43 vote.
"This bill is about the family farmer versus the big multinational company," Hands told the committee Tuesday.
The bill aims to set rules governing how companies, such as the biotech giant Monsanto Co., sample farmers' crops to determine if they are planting patented seeds they did not purchase.
Supporters of the bill say it's needed to protect Montana farmers from legal harassment that has cost innocent small farmers hundreds of thousands of dollars in other states. They say farmers' property rights should not be pre-empted by biotech companies' patent rights.
"These are common rights that everyone should have, including a thief," said Greg Matteson, a farmer from Shelby.
The bill would require that Monsanto and other companies get permission from a farmer before sampling crops on their land. If the farmer denies permission, the company could ask a district court for an order to sample the crops.
Monsanto's name came up many times in Tuesday's hearing, but the company did not testify.
However, Monsanto did give a private presentation to members of the committee on March 11 at the Montana Club, according to Sen. Cliff Larsen, D-Missoula, who chose not to attend.
Opponents of the measure told lawmakers it would discourage biotechnology companies from operating in Montana and shelter farmers who illegally "pirate" seeds.
"We believe the ultimate goal of this bill is to limit the opportunity of biotechnology coming into Montana," said Bing Vonbergen, president of the Montana Grain Growers Association.
The Montana Seed Trade Association, the Beet Growers Association of Montana and the Montana Farm Bureau Federation testified against the measure.
On the other side were the Montana Organic Association and a number of farmers and ranchers who appeared to testify for themselves, including Democratic Rep. Mike Jopek, a farmer from Whitefish.