The Defense Acquisition Program Administration(DAPA) has asked troubled shipbuilders that are undergoing a structural overhaul to exercise caution in the reduction of the workforce related to defense projects.

A DAPA official said Thursday that the administration recently sent letters to key shipbuilding firms, asking for prudence in downsizing departments and manpower related to national defense. 

The letters were delivered to five companies last Wednesday — Hyundai Heavy Industries, Daewoo Shipbuilding and Marine Engineering, Hanjin Heavy Industries and Construction, STX Offshore and Shipbuilding and Kangnam Corporation.

In the letter, the DAPA cautioned the firms against any possible violation of contract terms resulting from the restructuring process.

The agency is currently carrying out large-scale defense projects with the shipbuilding sector including the KDX project to develop a domestic destroyer.

The Jangbogo III program aimed at developing three-thousand-ton submarines for the Navy to deploy after 2020 is also handled by Daewoo Shipbuilding and Marine Engineering.