Japan's main opposition Liberal Democratic Party said it would look at establishing a permanent presence on the uninhabited Tokyo-controlled Diaoyu Islands - known as the Senkakus in Japan - which are also claimed by China.
The LDP also promised a review of the self-imposed ban on defending allies, offering the possibility of Japanese troops returning fire if US forces were attacked.
A move to examine the issues was part of a series of policy pledges ahead of December 16 polls. The document, presented by LDP leader Shinzo Abe, offered several reviews and studies, but stopped short of promises of action with binding goals.
Opinion polls suggest the LDP could be the largest party after the election, putting Abe in line for a return to the premiership, but it would need support from coalition partners to form a government.
The document said the party "will clarify the rights of self-defence, including collective self-defence, and legislate for a basic law on national security".
Collective self-defence refers to the right to take aggressive action when an ally is attacked, a right Japan already has, but has thus far refrained from using.
The country's pacifist stance enjoys widespread public support, despite it having been foisted on a defeated Japan by US occupiers after the second world war.
The LDP, which ruled Japan for an almost unbroken half-century before it was ousted in 2009 by the Democratic Party of Japan, said it would "study the stationing of public servants to protect" islands at the centre of a territorial row with China.
"We will review policies on the Senkaku Islands, which Japan has a policy of keeping unmanned despite the fact they are Japanese territory, so as to strengthen Japan's control over the islands," it said.
Party leaders say they want to achieve 3 per cent nominal growth, prioritising polices to exit from years of deflation and a higher yen. "Aggressive easing" and the quick implementation of a fiscal stimulus were prescribed, but no timescale was given on when the growth would be achieved.