By Christoph Steitz, Tom Käckenhoff and Vera Eckert

"What is important is that any new investor must be long-term and support the group's value and strategy," CEO Stefan Dohler told Reuters at an energy conference in Berlin.

Some European countries, most notably Germany and Denmark, have become more sceptical of critical infrastructure falling into the hands of foreign investors, with some intervening to avert such deals.

EWE, majority-owned by cities and municipalities in northwestern Germany, will begin the sales process in the first quarter, Dohler said, noting bringing in an outside co-owner would serve as a "healthy corrective" to the group's strategy.

The stake could be worth up to 1.6 billion euros ($1.82 billion) with potential bidders including a consortium of infrastructure investor Macquarie and Allianz, sources familiar with the process told Reuters this month.

Canadian pension fund OMERS, Australian infrastructure fund IFM and Dutch pension fund PGGM, all keen to invest in stable energy infrastructure assets, could also be interested, the sources said.

Dohler also said the group was in intense talks with a number of potential buyers for its operations in Turkey, where EWE is the fourth-largest natural gas supplier by number of customers.

However, EWE would only sell when the price is right, he said.

"There won't be a fire sale."

Turkish gas distributor Palmet last week said it was in talks to acquire EWE's Turkish business and estimated the deal at 130 million to 150 million euros.

($1 = 0.8808 euros)

(Editing by Thomas Seythal and Jason Neely)

By Christoph Steitz, Tom Käckenhoff and Vera Eckert