BOSTON--A new poll has again found Democratic candidates for statewide offices leading their Republican competitors by almost 2-1 margins or more except for the state treasurer's race.

The survey, conducted for The Boston Herald and WBZ-TV and released yesterday, found Gov. Michael S. Dukakis leading his GOP rival, George Kariotis, by 67 percent to 21 percent.

In the attorney general's race, former U.S. Rep. James Shanon led Republican Ted Harrington, a former U.S. attorney, by 50 percent to 26 percent.

Democratic Rep. Joseph DeNucci was ahead of Republican Rep. William Robinson, 47 percent to 20 percent, in the state auditor's race.

In the hotly contested treasurer's race, incumbent Democrat Robert Crane led Republican Joyce Hampers by 46 percent to 29 percent.

And Democratic Secretary of State Michael Connolly was leading his GOP challenger, Deborah Cochran, 43 percent to 23 percent.

The poll of 400 likely voters was conducted Sunday and Monday by KRC Research of Cambridge. The margin of error is plus or minus 5 percentage points.