SEOUL, South Korea - North Korea has transported its most advanced missile, believed to be capable of reaching Alaska, to a site where it could be ready for launch in a week or two, news reports said Monday.

The reclusive country was also reportedly strengthening its defences and conducting amphibious assault exercises along its western shore, near disputed waters where deadly naval clashes with South Korea have occurred in the past.

With the launch, Pyongyang could also thumb its nose at United Nations Security Council attempts to rein it in after last week's nuclear test and a series of short-range missile launches.

South Korean media have speculated that the North wants to time the launch for around June 16, when South Korean President Lee Myung-bak has a summit in Washington with President Barack Obama.

South Korea's Yonhap news agency said the missile had been sent by train to the newly completed missile facility of Dongchang-ni, 60 kilometres from the Chinese border.

Yonhap, quoting government sources, said the missile could be ready to launch in a week or two. South Korean defence and intelligence officials refused to comment.