AUGUSTA — Legislation to fine tune a 2007 law requiring small school districts to merge is proving to be contentious because changes backed by the Senate are coming under attack from the administration of Gov. John Baldacci.

The original bill backed by most members of the Legislature's Education Committee would lift financial barriers to consolidation by allowing communities to craft their own cost-sharing agreements when school districts merge.

But the Senate on Monday changed the bill to boost local control within merged districts. Now a spokesman for Baldacci says the governor opposes that change, which opponents see as weakening the consolidation law.

The Senate-backed change, which has yet to be considered by the House of Representatives, would allow districts that merge to retain local school boards, as well as some local control over budgeting.

A merged district would have one superintendent to oversee shared costs, including administrative expenses. But communities within a merged district could retain local ownership of their schools and control over such things as teacher salaries, if they chose to do so.

Supporters of the proposed change say it would save money and reduce the number of superintendents in Maine, while protecting local autonomy to a greater degree than the 2007 law does.

The House may take up the issue later this week.