DUESSELDORF, Germany, April 30 (Reuters) - Germany's IG

Metall union on Tuesday said it had held preliminary talks with

Carlyle and agreed to push for a "best and fair owner"

agreement for the investment firm to take a stake in

Thyssenkrupp Marine Systems.

In a newsletter, the union however insisted that a stake

sale to private equity investors could only happen if the state

stepped in as well to secure the conglomerate's naval

shipbuilding activities.

The economy ministry was not immediately available for

comment.

"A first round of negotiations in a small group is scheduled

for the beginning of May," IG Metall said.