Factbox: Details of Wisconsin's anti-union measure

(Reuters) - The Wisconsin state Assembly approved legislation to curb the power of public sector unions on Thursday. Governor Scott Walker is expected to sign it into law as soon as possible. Here are some details of the new law:

* State workers must increase contributions to their pensions to 5.8 percent of salary, and double contributions to their health insurance premiums to 12.6 percent. This would result in a cut in take-home pay of about 8 percent.

* Public sector union collective bargaining would be limited to the issue of wages, and cap increases to the rate of inflation, with a voter referendum needed for bigger increases.

* Employer collection of union dues would be prohibited and members of collective bargaining units would not be required to pay dues. Collective bargaining contracts would be limited to one year, and units must take annual votes to maintain certification as a union.

* Governor Walker said collective bargaining takes too long and the cuts need to be made immediately. He said the alternative would be layoffs of more than 10,000 government workers.

* Certain employees, including local law enforcement and firefighters, would be exempt from the collective bargaining restrictions.

(Reporting by Mary Wisniewski; Editing by Greg McCune)