The Democratic Party of Japan's presidential election is developing into an unexpectedly tight race, with Prime Minister Naoto Kan gaining 160 votes among the party's 412 Diet members, compared with the 170 of his sole challenger, Ichiro Ozawa, a Kyodo News survey showed Friday.

The situation remains fluid, however, as roughly 80 lawmakers either said they had not decided or refused to respond. They make up around 20 percent of the DPJ members in both Diet chambers.

The result indicates Ozawa, 68, the party's sandal-tainted former secretary general and ex-president, who was expected to chalk up more lawmaker votes than Kan because of his clout within the party, has so far failed to gain the full support of either the approximately 150 members in his intraparty group or the 60 members of the group headed by former Prime Minister Yukio Hatoyama, his close ally.

Both the Kan and Ozawa camps are expected to intensify their quest for votes among freshman lawmakers — who account for half of the swing votes — and local-level assembly members, as well as about 340,000 supporters nationwide.

Kan, 63, the current DPJ president, has the support of around 120 Diet members, including 50 from his own group, 40 from a group led by transport minister Seiji Maehara and 30 from one led by Finance Minister Yoshihiko Noda.

In office only three months since replacing Hatoyama, Kan has successfully racked up an additional 40 votes as a result of his efforts to woo support through meetings with freshman Diet members, including the "Ozawa Children," who were elected in recent national polls with the don's backing.