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

Metall union on Tuesday said it had preliminary talks with

Carlyle on the investment firm taking a majority stake in

Thyssenkrupp Marine Systems and agreed to push for an

agreement as quickly as possible.

In a newsletter seen by Reuters, 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, adding that Carlyle

was carrying out due diligence about taking a majority stake.

Thyssenkrupp said last month it was considering selling

a stake in its Marine Systems unit. Carlyle had confirmed its

involvement in the talks but declined to elaborate.

Thyssenkrupp is aiming to sell a stake of around 25% in

the unit mainly due to the burden of providing billions of euros

of guarantees to clients.

"...a sale to private equity investors can only happen

if the state assumes its responsibility and steps in to secure

naval shipbuilding as a key technology in the long term," the

union said.

"There is currently broad political support for this."