* Suez could buy out La Caixa's Agbar stake - newspaper
* Journal du Dimanche says GDF talked to Japan's Itochu
* Says Veolia in talks with Norway's sovereign wealth fund
* GDF, Suez deny report; Veolia not available for comment (Adds detail from newspaper report on Itochu, Veolia talks with Norwegian fund)
PARIS, May 4 (Reuters) - French utility GDF Suez and Suez Environnement on Sunday denied a report that Spanish group La Caixa would take a stake in the environmental services firm, replacing lead shareholder GDF Suez.
Suez Environnement would buy out La Caixa's minority stake in its 75 percent-owned Spanish water unit Aguas de Barcelona (Agbar) in exchange, French newspaper Le Journal du Dimanche reported, citing anonymous sources.
Agbar has extensive operations in Latin America.
The newspaper said Suez Environnement was expecting GDF Suez, which has a 36 percent stake, to pull out by the end of this year. The paper also said banks Nomura and Credit Agricole had studied the sale of a block of 10 to 15 percent of Suez Environnement stock.
Both GDF Suez and Suez Environnement denied the newspaper report to Reuters, saying there were no talks and no deal of this kind was being considered.
"We have no intention to reduce our stake in Suez Environnement, not even partially," a GDF Suez spokeswoman told Reuters.
In July 2013, GDF Suez let a 2008 shareholders' control pact of Suez Environnement expire. Since then, there have been several reports of a sale, which have sometimes had an impact on share prices.
However, both companies have consistently denied all reports about a possible transaction.
The paper also said that six months ago, GDF Suez had had talks with Japan conglomerate Itochu - with whom it plans to build a nuclear plant in Turkey - about selling part of its Suez Environnement shares.
It added that GDF had hired a consultant to advise on a new name for Suez Environnement, which would drop the "Suez" link.
Le Journal du Dimanche also said Suez competitor Veolia has started talks with Norway's sovereign wealth fund, which could double the fund's three percent stake in the group and give it a seat on the board.
It also said Saudi Arabia's sovereign wealth fund was interested in taking a Veolia stake.
Veolia was not available for comment.
Norway's fund has a 2.98 percent stake in Veolia, making it the fifth-largest shareholder after the sovereign wealth fund of Qatar, which has 4.51 percent, Thomson Reuters data show.
Veolia's lead shareholder, state-owned holding company Caisse des Depots (CDC), said last month it no longer saw its 8.85 percent stake as strategic.
The second-biggest shareholder, Groupe Industriel Marcel Dassault (GIMD), resigned from Veolia's board last month after an unsuccessful attempt to oust chief executive Antoine Frerot.
Frerot has said that Dassault could sell its 6 percent stake if Veolia's stock price rises. (Reporting by Geert De Clercq; Editing by Raissa Kasolowsky/Ruth Pitchford)