SYDNEY, Aug 21 (Reuters) - Australia will spend A$1.3 billion ($833 million) to boost its long-range strike capabilities as it finalised on Monday a deal to buy more than 200 Tomahawk cruise missiles from the United States, part of a wide-ranging defence shake-up.

Australia will be only one of three nations to have Tomahawks along with the U.S. and Britain, Defence Minister Richard Marles said.

"We are investing in the capabilities our Defence Force needs to hold our adversaries at risk further from our shores and keep Australians safe in the complex and uncertain world in which we live today," Marles said in a statement.

The U.S. State Department in March approved the sale of the Tomahawks, which have a range of 1,500 kms (932 miles), but did not indicate at the time that a contract had been signed or talks had concluded.

The ship-launched version of the missiles, manufactured by RTX Corp (RTX.N), will be deployed on the Royal Australian Navy's Hobart-class destroyers, he said.

Australia says it needs to upgrade its defence forces as China is undertaking the biggest military build-up since the end of World War Two.

Earlier this year it agreed to work with the United States and Britain to develop a nuclear-powered submarine fleet.

In addition to the Tomahawks, Australia would spend about A$431 million to purchase more than 60 advanced anti-radiation guided missiles from the United States, the defence minister said.

Long-range anti-tank guided missiles would also be bought for Australian Army's Boxer combat reconnaissance vehicles in a contract worth more than A$50 million.

The Tomahawk announcement came days after the U.S. approved a possible sale to Australia of M142 High Mobility Artillery Rocket Systems (HIMARS) for $975 million.