French utility GDF Suez has agreed to buy the 30 percent of British power producer International Power it does not already own for 418 pence per share, the companies said on Monday.

The offer, bolstering GDF's exposure to high-growth markets, is at a 7 percent premium to an earlier approach and values International Power at about 22.8 billion pounds ($36.2 billion).

International Power earlier this month rejected a preliminary approach by GDF that had valued the company at 19.9 billion pounds.

(Reporting by Adveith Nair; Editing by Paul Hoskins)