PORTLAND - A ballot measure that would extend Maine's legislative term limits from four to six consecutive terms picked up support from civic activist groups Thursday, a day after opponents released a study that says the present term limits law is working fine.

Common Cause Maine and the League of Women Voters of Maine were joined by other groups to announce their support for the proposal, which would let lawmakers serve a maximum of 12 years in a row instead of eight in either the Maine House of Representatives or Senate.

The proposal, sent to voters by the Legislature, would modify the law enacted as a result of a 1993 referendum. It will appear as Question 5 on next Tuesday's statewide ballot.

Alison Smith of the League of Women Voters called extended term limits a moderate reform that will address adverse effects of the present law.

Smith said extended term limits will do nothing to guarantee the re-election of incumbents. "Maine voters have always had the opportunity to retire legislators who do not adequately represent their districts," said Smith, adding, "we do that through elections."

Jon Bartholomew of Common Cause Maine said his primary concern about term limits is "the lack of accountability that comes from the shift of power from the legislative branch to the executive branch and lobbyists."

The supporters, who also include the Maine People's Alliance, spoke a day after the conservative Maine Heritage Policy Center released a new study highlighting the positive effects of Maine's current term limits.

Tarren Bragdon, director of Heritage Policy Center's health reform initiatives, said the study shows that more legislators are now serving with mid-level experience. Nearly two-thirds of legislators serve for at least six years, and there is more access to leadership positions, under present term limits, he said.