A man and woman have been charged following an alleged carjacking in Caroline Springs last night.

Police say the pair, armed with knives, threatened a man sitting in his car in a Ballarat Road carpark about 8.30pm.

They stole the vehicle, which was later seen being driven erratically. Police engaged in a brief pursuit before arresting a 21-year-old man and a 25-year-old woman, both of no fixed address.

The man has been charged with eight offences including aggravated carjacking, evading police, commit indictable offence while on bail and contravene conduct conditions of bail.

The woman has been charged with aggravated carjacking and commit indictable offence while on bail.

They are both expected to appear at the Melbourne Magistrates Court today.