Unions are throwing their support behind former city Managing Director Kirk Caldwell as he seeks to regain the office he held for 45 days in 2010.

Two of the state’s largest public worker unions, the Hawaii Government Employees Association and the United Public Workers, on Tuesday announced their endorsements of Caldwell for mayor.

Caldwell is running against the incumbent, Peter Carlisle, and former Gov. Ben Cayetano.

Union leaders said neither Carlisle nor Cayetano sought an interview to seek their endorsement.

"We think that we have not seen the leadership that this city needs out of the incumbent mayor, and we do not believe that the administration of former Gov. Cayetano has left a favorable legacy for all of us in Hawaii," said Randy Perreira, HGEA executive director. "We look at the needs of our city and county and feel that it’s going to take a well-rounded individual — someone who is committed to … paying attention to the little things as well as the legacy projects — to move our city forward."

In a newsletter emailed to HGEA members last month, the union criticized Cayetano for his "efforts to reduce employee rights through civil service reform."

A Star-Advertiser/Hawaii News Now poll earlier this month showed Cayetano leading the race with 44 percent, followed by Carlisle at 35 percent and Caldwell with 16 percent. The poll had a margin of error of 4.2 percentage points.

Cayetano said he was not surprised by the unions’ decision, adding that internal polls show that a majority of union members vote independently and are not influenced by leadership.

"The public worker union leaders fear and oppose any kind of reform to civil service, the retirement system and the health fund. They want to retain the status quo," Cayetano said in an email response. "Kirk is a nice man but he’s never had to make a tough decision in his entire political career. For them, he is the perfect candidate."

Carlisle said the endorsements were expected. In its newsletter, the HGEA said the Carlisle administration had taken a negative stance toward public workers.

"I hope most city workers who genuinely do work hard understand the necessity of shared sacrifice," Carlisle said. "There are private-sector workers who have been out of work for years with little hope of employment.

"I routinely disappoint public union bosses when I do not succumb to unreasonable demands to collect their political endorsements."

Caldwell, who was acting mayor after Mufi Hannemann stepped down to run for governor in 2010, also has been endorsed by the Hawaii Fire Fighters Association and the State of Hawaii Organization of Police Officers. The same four unions also endorsed Caldwell in his unsuccessful run in 2010.