HERNE, Germany, Sept 16 (Reuters) - Germany's

Thyssenkrupp must demonstrate its commitment to a

planned 3 billion euro ($3.3 billion) green steel site, the

country's Economy Minister Robert Habeck said, days after the

company flagged the project's cost may increase.

"It is very important that Thyssenkrupp clearly underlines

that it wants to stick with the project," Habeck told Reuters on

the sidelines of a visit to North Rhine-Westphalia. "If this

doesn't happen, it will be difficult for the entire site,"

Habeck said, without elaborating.

Thyssenkrupp Steel Europe (TKSE), in which Czech billionaire

Daniel Kretinsky owns a 20% stake, last week said the planned

direct reduction site in Duisburg could cost more than initially

expected.

Two people familiar with the situation, speaking on

condition of anonymity, have said the increase could be an

additional low-to-mid triple digit million euro sum.

In a statement on Monday, Thyssenkrupp said it was assessing

the situation and reiterated it had been informed of the risk of

a cost increase.

"We currently assume that the direct reduction plant can be

realised under the given framework conditions," the company said

in emailed comments.

Steel production is a big contributor to carbon emissions

and the industry has been trying to shift to green production

that does not rely on fossil fuel.

($1 = 0.8991 euros)