North Korea said on Wednesday that leader Kim Jong Un observed the first test-firings of missiles from a newly-launched destroyer and called for accelerating efforts to boost his navy's nuclear attack capabilities.

North Korea last week unveiled the 5,000-tonne warship equipped with what it called the most powerful weapons built in its warship industry.

Kim said it was a significant advancement toward his goal of expanding the operational range and pre-emptive strike capabilities of his nuclear-armed military.

The official Korean Central News Agency said on Wednesday that Kim watched the tests of the destroyer's supersonic and strategic cruise missiles, anti-aircraft missile, automatic guns and electronic jamming guns earlier this week.

He appreciated the ship's combination of powerful strike weapons and conventional defences and set tasks to speed the nuclear-arming of his navy, the report said.

During the ship's launching ceremony, Kim said the destroyer would be deployed early next year.

He said the acquisition of a nuclear-powered submarine would be his next big step in strengthening his navy.

He underscored the need to beef up North Korea's deterrence capability to cope with what he called escalating US-led hostilities targeting the North. (AP)