LONDON, May 9 (Reuters) - European discount retailer Action delivered sales growth of 20.9% in the first quarter, the chain's private equity owner 3i said on Thursday, as the company expands its store network and attracts more people shopping on a budget.

Net sales rose to 3.004 billion euros from 2.485 billion a year earlier.

Action, which is owned by private equity owner 3i Group, has stores in 12 European countries, having opened its first store in Portugal in February. Overall it added 303 new stores last year.

Action's largest store network is in France, with Germany and the Netherlands also core markets. (Reporting by Helen Reid; editing by Jason Neely)