COSTA MESA — An injunction prohibiting the city from outsourcing employee-performed work to private companies will remain in place after the California Court of Appeal in Santa Ana on Thursday threw out the city's petition to have it lifted.

The three-judge panel — consisting of Acting Presiding Justice William Rylaarsdam, and associate justices Richard Aronson and Raymond Ikola — dismissed Costa Mesa's 43-page petition for a writ of mandate.

"Courts continue to reject any justification for the City Council majority's outsourcing scheme," Orange County Employees Assn. spokeswoman Jennifer Muir said in a news release. "We sincerely hope this latest rebuke by the courts will motivate the council to abandon its needless campaign against its employees and all the residents who have urged them to stop dismantling the city."

In a prepared statement of their own, city officials said they're undeterred.

"Obtaining writ relief is difficult," City Attorney Tom Duarte said in a news release. "It is even more difficult still where there is a right to appeal the original ruling, which is the case here. The city will now proceed with a formal appeal of the trial court's preliminary injunction ruling."

Jones & Mayer, the law firm that represents the city, argued that Orange County Superior Court Judge Tam Nomoto Schumann's ruling was unconstitutional and premature. They also argued that she overstepped her authority by issuing the injunction simply because the city could be breaking the law — an assertion the city says remains unclear.

In July, Schumann told the city's attorneys that Costa Mesa could continue to explore outsourcing up to half the city workforce to anyone it wants, but could only lay off workers if they were being replaced with other public-sector workers, such as those county or neighboring city employees, not private contractors.

The City Council majority is seeking to outsource more than a dozen city services in an effort to offload future pension obligations, which are projected to grow in the coming years, and reinvest heavily in capital improvements.

Schumann's ruling was based on a city employees' lawsuit that claims the city is trying to outsource jobs designated as "special" services that can't be replaced by private companies under state law.

The injunction will remain in place until a judge or jury makes a ruling on the legality of Costa Mesa's attempted outsourcing to private firms.