His comments came as South Korean media reports said the North had finished construction of an underground fuelling facility close to a key launch pad on the country's east coast.
North Korea has said it is preparing to launch a satellite and has defended that it says is its right to develop its own space programme.
But its neighbours and US intelligence officials believe the test is actually of a long-range missile, the Taepodong 2, which experts say could reach as far as Alaska or the US west coast.
The technology for rockets used in space flight and for ballistic missiles is largely the same, with the only major difference being the payload – either a satellite or a warhead.
On Wednesday North Korean television reported that Kim had visited the province where the launch site is located.
The report showed what it said were new photos of the North Korean leader inspecting several sites in North Hamkyong province, including a bank office and a cigarette factory.
One photograph even showed Kim apparently smoking a cigarette, six months after he reportedly suffered a stroke.