BATH — The Department of Defense has awarded Bath Iron Works a $23 million contract modification to continue work on the DDG 51 class of destroyers.

The funds will allow BIW to provide further planning, design and liaison work for the destroyers, BIW spokesman Matt Wickenheiser said Monday.

“This is money we had planned for and anticipated,” he said. “It’s not new work, but it’s good, solid work and allows us to keep doing the work we’ve been doing.”

The work will be performed at the Bath shipyard, according to the Department of Defense.

Bath Iron Works is the lead yard for the Arleigh Burke-class guided missile destroyers. The Navy planned to replace the DDG 51 with the high-technology Zumwalt class, but in 2008 the Pentagon changed course because of concerns about the cost to build the Zumwalt.

In June, the Navy awarded BIW contracts for four new DDG-51 destroyers, with the option for a fifth.