Shorten dodges South China Sea questions

Labor leader Bill Shorten has avoided backing two of his senior frontbenchers who said a decision on conducting freedom-of-navigation operations in the South China Sea should be left to the military.

Asked three times about the comments of his defence spokesman Richard Marles and foreign affairs spokeswoman Penny Wong, Mr Shorten spoke generally about the disputed territory and called on involved countries to peacefully resolve the situation through diplomacy.

"In terms of Australia military operations, I'm not going to start telling the military how to sail their ships but what we do recognise is that this is that the government, and they have, should give political authority to make sure we uphold freedom of navigation," he told reporters in Canberra on Wednesday.

In separate interviews on the sidelines of the Australian-American dialogue in Hawaii last week, Senator Wong and Mr Marles said a Labor government would authorise the military to conduct freedom-of-navigation exercises but not tell Defence command how or when ships or aircraft should approach one of China's claimed islands.

Prime Minister Malcolm Turnbull blasted the Labor frontbenchers in parliament on Tuesday, saying such decisions were political and must be made by the people's representatives.

Labor's public discussion showed immaturity and an unreadiness to take responsibility, he said.

Former prime minister Paul Keating has also been scathing, saying such decisions should not be outsourced to naval commanders or even admirals.