UPDATE 1-NBC plans about $2.5 bln offer for NBA broadcast rights, WSJ reports

(Adds details from the report throughout)

April 29 (Reuters) - Comcast's NBCUniversal is planning to pay an average of about $2.5 billion a year to broadcast a package of National Basketball Association (NBA) games, the Wall Street Journal reported on Monday, citing people familiar with the matter.

Warner Bros Discovery's TNT has paid an average fee of $1.2 billion under its current deal, but was unable to reach a new pact with the NBA before an exclusive negotiating window expired last week, according to the report.

Warner began airing the games in 1984, while Walt Disney's ESPN sports network began broadcasting the NBA in 2002.

Disney is expected to pay an average per-year fee of about $2.6 billion to renew its deal, WSJ reported, citing sources, up from about $1.5 billion per year now.

NBCUniversal and its parent Comcast, Warner Bros Discovery, and the NBA did not immediately respond to Reuters requests for comment. Disney-owned ESPN declined to comment. (Reporting by Jaspreet Singh in Bengaluru; Editing by Anil D'Silva)