Sydney - Animal rights activists demonstrated outside a Canberra military base Friday as sharpshooters inside the fence went about killing around 400 kangaroos at risk of death from starvation.

Contractors have been engaged to shoot the kangaroos with tranquilizing darts and then kill them with lethal injections.

There are around 600 kangaroos on the 200-hectare base and the Defence Force said there was only enough food for 200.

"It has to comply with the national code of practice for humane destruction of kangaroos," Defence spokesman Brigadier Andrew Nikolic said.

Last year protestors stopped the cull going ahead after they pledged to put themselves between the shooters and their quarry.

An alternative plan to relocate the marsupials was blocked by the government.

Earlier this year Environment Minister Peter Garrett, the former Midnight Oil singer, said he was unmoved by threats from London-based animal welfare group Viva! to organize an international boycott of Australian goods and services if the cull went ahead.

"When there are significant imbalances ... then programmes like this, humanely and properly administered, are sometimes necessary," Garrett said.

The Defence Force has reverting to its original plan - killing the kangaroos - which has always been the preference of animal rights organization RSPCA.
Kangaroos are plentiful and a permit system allows hunters to kill upwards of 5 million a year. The meat mostly ends up as pet food.

The kangaroo population varies from 25 million to 80 million, depending on whether the continent is in drought or not. There are more kangaroos now than when white colonists arrived in 1788. (dpa)