ROCKLAND, Maine — The City Council voted unanimously Wednesday night to put both its City Hall property and the adjacent public works garage up for sale for an undisclosed development.

There was no debate before the 3-0 vote by the council. Councilors Larry Pritchett and Louise MacLellan-Ruf were absent from the brief meeting.

The council held a closed-door meeting for an hour Monday night on an economic development matter and declined to answer questions about it. The council also held a closed-door meeting in September 2013 about potential development value of the City Hall property, which is located off Route 1 near the Thomaston town line.

Bids for the 18 acres are due April 27.

A proposed development that led the City Council to consider putting the property up for sale first was raised last Thursday.

Details about who is interested in the property or what the developer hopes to do are not being released just yet, but City Manager James Chaousis said more information will be made public soon. He said he has been in discussions with a potential developer for the past couple of weeks and that on Thursday, April 9, interest in city property was raised.

The property where City Hall and the public services garage are located is zoned for industrial use. The City Council, however, could change the zone to meet the needs of some other type of development. Some of the rear portion of the city property, however, is in a shoreland protection zone because of wetlands.

Chaousis said Wednesday he is not aware of any conflict between the project and the zoning.

The city manager said the City Council’s meeting on Monday night needed to be held behind closed doors so as to not prejudice the city’s negotiating position with the developer through a premature release of information. He said once the development is announced, he would explain.

The city has not yet looked at any alternate locations for City Hall or public services, he said.

Once the bids are opened, the City Council would review the offers and decide whether to grant an option to a buyer. At some point, a purchase and sales agreement could be signed.

In November 2013, then Community Development Director John Holden said Rockland, in general, has limited areas for future commercial development. One area where there is potential for development is the west side of the city near the Thomaston line where City Hall and public works are located, Holden concluded.

Rockland bought the City Hall property in 1995 from the Camden-Rockland Water Co. and renovated the office building before moving into it in March 1996. Before than, City Hall was located in the train station.

The city has owned the public works property since 1962. City officials have tried twice to get voter approval for a new public works garage without success. The most recent rejection came in November 2011 when residents voted 895-881 against borrowing $2.9 million. The city had discussed building a new garage on city-owned land near the solid waste facilities.