MADRID (REUTERS) - Barcelona have extended to 2016 a deal with Unicef under which the La Liga side pay US$2 million (S$2.5 million) a year to display the name of the United Nations Children's Fund on the back of their shirts.

The current agreement was due to expire next year and the Barca directors approved a two-year extension at a board meeting on Tuesday.

Barca and Unicef first joined forces in 2006 and Barca's Argentine World Player of the Year Lionel Messi is one of the fund's global goodwill ambassadors.

The club used to have the Unicef name on the front of their shirts, which made them one of the few sides in soccer not to display a corporate logo.

They agreed a sponsorship deal with Qatar Sports Investment worth 30 million euros (S$50.2 million) a season in 2011 and the shirts now feature the name of airline Qatar Airways.

Dropping the Unicef name to the back was controversial and prompted accusations the club was selling out and compromising their ideals for material gain.

Barca officials argued that the injection of cash at a delicate time for the club's finances was needed to help fund the development of their sports teams and help them compete with wealthy rivals.