THE federal government has secretly wound back a critical environmental protection for the Great Barrier Reef against shipping accidents in order to avoid a diplomatic stoush with the United States and Singapore.

Leaked US embassy cables published by WikiLeaks have revealed that the government has "weakened" the compulsory pilotage regime for large vessels, including oil tankers, chemical tankers and liquefied gas carriers, sailing through the sensitive maritime environment of the Torres Strait.

Under threat ... the Great Barrier Reef. Credit:Dave Wachenfeld

Owners and masters of vessels that fail to use a pilot to navigate the narrow and hazardous channel will not face any penalty if they do not subsequently call at an Australian port.

On learning the Torres Strait pilotage regime was quietly amended 17 months ago, the chief executive of the Australian Conservation Foundation, Don Henry, said it was "absolutely essential'' that all shipping [through the strait] has pilotage.