Heightened tensions
Abe's government responded to North Korea's nuclear test on October 9 by imposing sanctions and calling on the UN Security Council to pass a resolution to punish Pyongyang.
Six-nation talks last month intended to persuade the North to abandon its nuclear weapons programme failed.
"The security situation surrounding Japan has changed drastically with the proliferation of weapons of mass destruction and missiles as well as a series of regional conflicts," Abe said.
"In order to guarantee peace, stability, independence, freedom, democracy and to protect the lives of Japanese people, we need to further strengthen the US-Japan alliance."
As part of that alliance, Tokyo and Washington are to discuss plans in February for their troops to jointly deal with a potential conflict between China and Taiwan.
Defence and foreign affairs officials are to assess possible crisis situations that could occur across the Taiwan Straits, the Kyodo news agency reported, citing officials from both countries.
Abe's predecessor, Junichiro Koizumi, told parliament in 2005 that Japan did not anticipate providing military co-operation to the US for any crisis in the Taiwan Strait.
Japan's military contribution would be limited under its pacifist constitution to providing supplies, transport and medical services, Kyodo said.
Charter change
But Abe said on Thursday that he would revise the constitution and would seek voter support for the change in this year's national election.
"My cabinet will aim to revise the constitution and I intend to seek support for it during the upper house election," Abe said.
Abe's ruling Liberal Democratic party released its draft for a new constitution in 2005 that would recognise Japan's right to maintain a military.
Japan abandoned the right to wage war or maintain a military under the 1947 constitution drawn up by US occupation authorities after the second world war, but it has forces for self-defence.
Revising the constitution requires approval of two-thirds of both houses of parliament and then a majority of the voters in a referendum.
Surveys have shown that voters are evenly split between those for and against changing the constitution.