The US will create the world's largest marine reserve, stretching over about 1,270,000 sq km of the Pacific ocean, the White House press service said.
US President Barack Obama will sign the bill Thursday, setting out plans for a new environmental zone encompassing seven desert islands and coral atolls existing under US jurisdiction.
The current Pacific Remote Islands National Marine Monument territory between the Hawaiian islands and Samoa will be expanded six-fold to become a marine-protected area (MPA).
The zone will ban any business activity there, including commercial fishing and mining operations.
American scientists believe the region has a tropical marine environment with unique animal and plant life that need protection, seeking to defend deep-sea coral reefs thought most vulnerable to the impacts of climate change.