(CNN) -- California's Supreme Court on Monday upheld Gov. Arnold Schwarzenegger's furlough order for state workers, according to court documents.
Schwarzenegger ordered the furloughs in 2008 in an effort to help the cash-strapped state. The order required state workers to take two unpaid days off per month. The number of days was bumped up to three in 2009 as revenues continued to plummet.
The furloughs -- the latest of which were renewed in August -- are estimated to save the state $80 million a month.
The Professional Engineers in California Government union was among several employee organizations that sued on the grounds that the governor does not have the authority to furlough employees. It urged the state Supreme Court to rule that the furloughs are illegal.
But in the court's ruling filed Monday, the court rejected the plaintiffs' challenge on the basis that the furlough plan was endorsed by the California legislature and was not unilaterally enforced by Schwarzenegger.
"As Governor, I have had to make very difficult decisions in response to the world-wide economic collapse, including furloughs for state workers and line-item vetoes to balance our budget," Schwarzenegger said in a statement in response to Monday's ruling. "These decisions were absolutely necessary to keep our state functioning. Today's ruling upholds the state's actions to protect taxpayers and ensure we live within our means, just like every California family and business must do."