OUT OF SORTS: Liam Payne didn't know how to respond when a girl was peeking at him while he was lying in bed.

Liam Payne remains angered by a crazed fan who tried to break into his hotel room last week.

The One Direction singer was bewildered after performing in Sydney, when he awoke to discover a female admirer had scaled the wall to his second floor room.

The 20-year-old had left his boxer shorts on the balcony to dry after a surfing trip and was lying naked in his bed during the incident.

He's stunned no legal action has been taken against the young woman who was pictured wearing the underwear the very next morning.

"When you're butt naked and there's a stranger looking through the window, it's scary," Liam told UK newspaper The Sun.

"If you flip it the other way round and it was me looking through the window, I'd have been straight off to jail."

Liam said the moment he met eyes with the girl was one of his most vulnerable.

He remembers thoughts racing through his mind about how to handle the situation had it escalated.

"I was in bed and heard something bang on my balcony. Out of nowhere I saw these eyes peering through the crack of the door," Liam recalled.

"She started opening the door. I was like, 'What do I do? I'm naked'. I shouted for security and she ran off."

Liam and his One Direction bandmates Harry Styles, Niall Horan, Zayn Malik and Louis Tomlinson are returning to Australia this week after wrapping up three dates in New Zealand.

The band completes its Take Me Home Tour in Tokyo November 3.