Sweden coach Lars Lagerback admits David Healy poses a big threat to his side when they face Northern Ireland in top-of-the-table Euro 2008 qualifier on Wednesday.

The striker scored a superb hat-trick on Saturday, his second of the campaign, in the 4-1 victory against Liechtenstein to take his international record to 27 goals in 55 appearances.

Lagerback left Sweden's training camp in London to witness Healy's exploits in Vaduz at first hand.

He said: "Healy is always running and shoots from every angle. He is very effective. If they can, Northern Ireland play directly at him. It's important that Olof (Mellberg) and the boys watch him and do not let him in behind the defensive line.

"But they have been good at controlling fast players in earlier matches."

Northern Ireland will replace - who have a 100 per cent record - as leaders if they get a victory at Windsor Park and Lagerback added: "They are a tricky team."