May 16, 2002 11:00 pm

PORTLAND (AP) — Ted Kulongoski continues to enjoy a healthy lead in the Democratic race for governor while the Republicans are in a nailbiter, according to two new polls released late Thursday.

An Oregonian/KATU poll included 307 likely Republican primary voters. It found Kevin Mannix with 29 percent, Ron Saxton with 27 percent and Jack Roberts with 19 percent.

Kulongoski, the former state attorney general and Supreme Court justice, is supported by 40 percent of likely Democratic voters. His two rivals, former state treasurer Jim Hill and former Multnomah County chairwoman Beverly Stein, remain far behind, with 23 percent for Stein and 19 percent for Hill.

The poll sampled 300 Democrats. Both polls had an error margin of 5.5 percentage points.

A Portland Tribune/KOIN poll found the three Republican candidates in a statistical dead heat. Saxton had 30 percent and Mannix and Roberts had 27 percent each. On the Democratic side, Kulongoski had 40 percent, Hill 28 percent and Stein 20 percent. The polls had an error margin of 3.5 percent.

‘‘There's a very high probability that Ted Kulongoski is going to win the Democratic primary,'' said Tim Hibbitts, whose firm conducted The Oregonian poll. He said that for Hill or Stein to win, one of them would have to attract nearly all the undecided voters.

The new survey indicates recent attacks against Saxton, both by his rivals and by social conservatives who don't like his support for abortion rights, had stopped his rapid rise in the polls.

Saxton, a Portland attorney and former school board member, had been unknown to most voters until he started a saturation advertising campaign a month ago.

Mannix, the former legislator and Salem lawyer, has appeared to keep a solid base of support that he has nurtured by stressing his conservatism on most issues, such as abortion.

‘‘People are not really jazzed about this election anyway,'' said Amy Casterline, Mannix's campaign manager. ‘‘The only passionate people are the conservatives and they are passionate about Kevin.''

Hibbitts said the Republican race is still too fluid to make any predictions.

He said there are a relatively large number of undecided voters and it's unclear just how many people will return their mail-in ballots before Tuesday's deadline.

The Hill and Stein campaigns questioned the poll numbers, believing the Democratic race is closer.

Kulongoski, whose political career stretches back to nearly three decades in Oregon, has run particularly strong among older voters, who Hibbitts thinks will make up nearly half of the primary electorate. Kulongoski has pitched his advertising toward those voters and 47 percent of those age 55 or older say they support him.

‘‘The real poll is Election Day,'' said Kulongoski's campaign manager, Sean Sinclair. ‘‘But we're happy where we're at.''