LIHUE, Hawaii, Dec 6 (Reuters) - Critics of genetically modified crops have introduced new measures to limit the spread of biotech corn, soy and other crops on the Hawaiian island of Maui, pushing back against companies that want to use the tropical region as a testing ground.

Maui County Councilwoman Elle Cochran introduced a bill on Friday that would require companies to disclose when they use pesticides and genetically modified organisms (GMOs) on the island.

The bill is modeled after a measure approved on the island of Kauai last month that controls the planting of biotech crops and the use of pesticides by agrichemical companies.

The Kauai bill requires large agricultural companies to disclose pesticides and GMOs, as well as establish buffer zones around schools, homes and hospitals. Similarly, the Maui bill targets companies that use more than five pounds or 15 gallons of restricted use pesticides annually.

On Thursday, Hawaii Island Mayor Billy Kenoi signed into law a measure that prohibits biotech companies from growing any new genetically modified crops on the largest of the archipelago’s islands.

An exception to the new law is GMO papaya, which has been genetically altered to resist disease and is now extensively grown in Hawaii.

“Today our communities expect that government will be as cautious as possible in protecting our food and water supplies,” Kenoi said in a statement.

“This ordinance expresses the desires and demands of our community for a safe, sustainable agricultural sector that can help feed our people while keeping our precious island productive and healthy.”

The Hawaii law goes into effect immediately and includes fines of $1,000 per day for noncompliance.

The measures in the Hawaiian islands are part of a larger battle brewing in the United States and several other countries. Biotech crop critics argue that genetically modified crops, first introduced in 1996, lead to increased pesticide use, environmental damage and health problems for people and animals.

The most popular biotech crops are corn and soybeans that have been genetically altered to make the plants tolerant of chemical herbicides and resist pest damage. Farmers say using biotech crops improves production and makes fighting weeds easier.

The biotech crop industry has been fighting back against measures such as those in Hawaii and recent moves in other U.S. states to require the labeling of food containing genetically modified ingredients.

The companies assert that biotech crops are essential to boost global food production and improve environmental sustainability. They say the crops and the pesticides used on them are used safely and are already well regulated by state and federal agencies.

The leading biotech crop companies include Monsanto Co , DuPont, Syngenta AG and Dow AgroSciences, a division of Dow Chemical Com.