July 30, 2010 –   * Plans to invest are at an early stage - sources

* Nokia Siemens Networks recently bought Motorola unit

(Adds background, Bain Capital)

By Megan Davies

NEW YORK (Reuters) - Blackstone, TPG Capital and Bain Capital are among private equity firms eyeing a stake in wireless network equipment maker Nokia Siemens Networks, sources familiar with the situation said.

Plans to invest in the firm, owned by Nokia and Siemens, are at an early stage, the sources said.

The Wall Street Journal, which first reported that several private equity firms were interested in Nokia Siemens Networks, said a stake in the firm would cost at least $1 billion.

Represenatives of Nokia and Nokia Siemens declined to comment, while efforts to contact a Siemens representative were unsuccessful.

Earlier this month, Nokia Siemens Networks struck a deal to buy Motorola's telecom network equipment business for $1.2 billion in an effort to penetrate the U.S. market, where it has struggled.

The U.S. market generates only 6 percent of its revenue.

Nokia Siemens Networks also recently won an eight-year contract worth more than $7 billion with an upstart U.S. operator called LightSquared, which is looking to build a high-speed wireless network to offer wholesale services in the fiercely competitive market.

Motorola and Nokia Siemens Networks have had a hard time battling bigger players to win business with large telephone companies in the cutthroat mobile gear market.

(Reporting by Megan Davies; additional reporting by Sinead Carew in New York and Jessica Hall in Philadelphia; Editing Gary Hill and Ted Kerr)