Ericsson, the world's top mobile network infrastructure supplier, is in pole position to buy the business support systems (BSS) unit of rival Nokia Siemens Networks (NSN), Dow Jones Newswires reported on Monday.

In addition to Ericsson, U.S. telecoms equipment maker Amdocs is also interested in the BSS unit, which provides billing and charging systems for telecoms operators, Dow Jones quoted a source familiar with the matter saying.

A source familiar with the situation told Reuters the unit was among assets NSN was considering selling, but could not confirm a deal was imminent.

Ericsson and NSN, a joint venture between Nokia Oyj and Siemens AG, declined to comment. Amdocs was not immediately available for comment.

NSN is in the middle of a slimming program that will also cut 17,000 of the group's workforce - or almost a quarter of the total - in an effort to improve its finances.

Sweden-based Ericsson has been expanding rapidly in BSS and operations support systems (OSS), last year buying Telcordia in the United States for $1.1 billion.

A recent survey by consultancy Gartner ranked Ericsson top globally by revenues in OSS and BSS services, including sales acquired with Telcordia.

NSN made a profit of 27 million euros on a non-IFRS basis in the second quarter on sales of 3.3 billion.