NOVI, Mich. -

Organized labor and pro-business groups are waging an intense lobbying campaign directed at Michigan teachers who are deciding whether to remain in their union.

The teachers' decisions will be the first big test of the state's new right-to-work law.

Special section: Michigan's new right-to-work law

Many of the 112,000 school employees in the Michigan Education Association can now leave the union and stop paying fees under the law that took effect last year. Union leaders are urging them to stay or risk losing their say in school policies. Conservative groups are running ads publicizing the chance for teachers to save their dues money, which can amount to $1,000 annually.

The deadline for deciding is Sunday. Contracts for most other major union groups don't expire until 2015 or later.

Related: Teachers sue MEA union over collection of union dues