'Work, work, work,' van Gaal urged after taking training for the first time in his second spell at the Catalan club.

'If we work hard this year then maybe we have a chance of winning something.'

Van Gaal won two league titles during his first spell in charge at Barcelona from 1997 to 2000.

His reappointment follows two barren seasons under Llorenc Serra Ferrer and Carles Rexach and the Dutch coach warned that getting back to winning ways would be difficult.

'For the last two years this team, helped by five or six very good players who have now left, failed to win anything,' van Gaal said at a news conference after his squad, minus players who featured at the World Cup, returned to work.

'We can't now say it's going to be easy.'

Van Gaal confirmed that Juan Roman Riquelme, the Argentine midfielder signed from Boca Juniors in an $11 million deal, could be sent out on loan for his first season.

'I always look to the long term,' said van Gaal, who already has a maximum of four non-European Union players in his squad. 'Riquelme is a fantastic player and he was available at a very good price.

'We'll see how things go but obviously if we've agreed a clause that says he could go out on loan then that is a possibility.

'I'm very happy with the signing. He can triumph here.'

The biggest question faced by van Gaal concerns the situation of Rivaldo, the Brazilian forward who played such a big part in his country's World Cup win in South Korea and Japan.

Rivaldo insists he has no desire to leave the club, despite much publicised problems with van Gaal in the past, but he is out of contract in June 2003 and if Barcelona cannot persuade him to sign an extension to his current deal they may have to act.

'Rivaldo has said he wants to triumph here and I'm delighted to have players with that kind of attitude,' van Gaal said.