STOCKHOLM (Reuters) - A wave of car burnings across Sweden that has seen more than 2,000 vehicles damaged or destroyed this year, moved on Monday night to the Stockholm suburb of Husby, where mass riots began three years ago and spread across the capital's poorer suburbs.

Police have arrested only one suspect - a 21-year-old man in the southern city of Malmo whose car contained cans of gasoline - and they are appealing for help nationwide in a country that prides itself on its low levels of crime.

"This crime is very hard to investigate," Malmo police's Lars Forstell said. "We don't see any patterns and we don't have any suspects."

"We need all the help we can get," he said.

On Tuesday, the centre-right opposition called on the government to act and the Justice Department told Reuters that an action plan would be presented in the "next couple of days".

The fires have centred on Stockholm and Malmo - Sweden's third biggest city, and 2,027 vehicles have been set on fire in total between January and July, according to the Swedish National Council for Crime Prevention.

In August alone, 48 vehicles were set on fire in Malmo and 60 more in June and July. On Monday, 13 cars were set alight in several different parts of the city.

Late on Monday, two cars were set on fire in Stockholm's Husby and seven cars were set on fire in the southern suburb of Haninge. No arrests have been made.

"We can't say if it is youngsters or criminals or whatever. We assume little things but we don’t know," Stockholm police spokesperson Kjell Lindgren said.

The 2013 riots started a debate about social inequality, poverty and immigration in Sweden and Malmo University criminology researcher, Manne Gerell, said it was typically disadvantaged young men who were responsible for the fires.

"There are a few major reasons. One that is often mentioned is that these youth or young men, when interviewed, say it is fun or exciting," he said.

(This verison of the story has been refiled to remove reference to Husby as a ghetto)

(Reporting by Violette Goarant and Johan Sennero; Editing by Louise Ireland)