A man who allegedly assaulted several people and threatened one with a knife while waiting to pat koalas at an Adelaide Hills wildlife park has been arrested.

Police say the Para Hills man, 34, became aggressive and assaulted one victim at the park about 11:30am on Saturday.

Two bystanders tried to intervene and the man then allegedly assaulted them and a staff member.

Police say at one point he brandished a knife to threaten one of the victims.

They say he drove off before they arrived but he was arrested on Monday.

The man was charged with two counts of assault as well as aggravated assault and was given police bail.

He will appear in the Mount Barker Magistrates Court in March.