Youth crime is falling.

That's despite the latest shocking case of nine youths, including one 10-year-old, being picked up by police in relation to two serious assaults in Auckland.

One of them, an attack on a couple in Myers Park in the early hours of Sunday morning.

Rod Bell, chief executive of the Blue Light charity, says while public perception may be that more children are committing violent crimes - it's not the case.

"The number of young people getting in trouble is reduced and the amount of crime committed by young people is getting less and less, which is fantastic."