THE Howard government urged the United States to force the collapse of the North Korean regime by denying it aid, despite advice that the country had a growing nuclear arsenal and could unleash an artillery barrage on South Korea's capital at a moment's notice.

''Let the whole place go to shit, that's the best thing that could happen,'' the foreign affairs minister, Alexander Downer, told the commander of US and United Nations forces in South Korea at a meeting in Canberra in 2005.

"Let the whole place go to shit, that's the best thing that could happen." ... Alexander Downer. Credit:Peter Braig

A leaked US embassy cable reports that Mr Downer told General Leon LaPorte that the outside world should sharply increase pressure on North Korea, suggesting that ''aid that could prop up [North Korea's] failing infrastructure should be withheld to bring an end to the regime's tyranny''.

The cable, obtained by WikiLeaks and made available exclusively to the Herald, says Mr Downer's ''off-the-top of his head'' remarks also derided New Zealand's approach to the Korean problem.