* GDF Suez, International Power talks ongoing, no timeframe
* International Power shares up 5.3 percent
(Adds International Power no comment, updates share prices)
By Muriel Boselli
PARIS, Jan 18 (Reuters) - French power and gas company GDF Suez is in talks with British group International Power about a possible asset swap to expand in growth markets, a person familiar with the matter told Reuters on Monday.
There is no detailed timeframe for a possible deal, the source said. "The (GDF Suez) group culture is one of partnerships and asset swaps, not cash deals. The talks are ongoing."
"International Power is a group that is potentially in line with the strategic development of the group," the source said.
The Sunday Times reported GDF Suez may make a takeover bid for International Power, while the Financial Times reported on Monday the companies had held discussions about creating a partnership involving foreign assets.
GDF Suez and International Power had no comment.
GDF Suez is the world's second-largest utility by market value, after power giant EDF, with a capitalisation of some 64 billion euros ($92 billion), compared with 4.9 billion pounds ($8 billion) for International Power.
GDF Suez has a limited presence in Britain, while EDF has expanded in the country with the 12.5 billion pound purchase of British Energy.
"This move makes total sense for GDF Suez," an analyst said.
GDF Suez chief executive Gerard Mestrallet has said the focus of the group born from the union of Suez and state-owned Gaz de France in July 2008 is on organic growth through investments in industrial projects.
But the group has said it would not rule out small or medium-sized acquisitions from time to time.
International Power delivers energy under contract to some 4 million households. It has 45 power plants in Europe, the United States, Asia and the Middle East.
Shares in International Power were 5.3 percent higher at 338.9 pence at 1323 GMT, after earlier rising over 9 percent. GDF Suez shares were up 2.4 percent at 29.025 euros.