North Korea has accused Japan of "railroading the security bills" that are "worked out to pave the way for invading other countries", the state media KCNA reported on Sunday.
"The enactment of the 'security law' helps Japan stage military operations in every part of the world under the pretext of protecting peace and security and assisting the US forces and dispatch the Self-Defence Forces overseas any time," said a statement issued by a foreign ministry spokesman on Saturday.
"Japan's militarist moves are posing a grave threat to peace and stability in Asia and the rest of the world," the statement said.
North Korea will further increase war deterrence to cope with it as the situation has proved the country's decision to bolster its self-defence capabilities was just, it said.
The Japanese Parliament's upper house on Saturday enacted a controversial legislation pushed forward by the government under Prime Minister Shinzo Abe.
The legislation's enactment marked an overhaul in Japan's purely defensive defence posture, meaning the country could dispatch its troops overseas to engage in armed conflicts for the first time in seven decades.