A taxi driver has tackled a woman to the ground in a dramatic citizen's arrest after a string of robberies and car jackings across Perth.

Video footage shows the man grabbing the woman from behind and eventually dragging her to the ground outside the IGA supermarket at Koondoola.

Witnesses say the taxi driver yelled "I've got the bank robber!". With the help of two other men, the woman was held until the police arrived.

It is alleged the woman had earlier forced the taxi driver at knifepoint to take her to the Koondoola supermarket.

Police allege the crime spree began just before 7:00am (AWST) on Tuesday when a man was robbed at knifepoint at a Padbury service station.

The female offender fled in a stolen utility.

The woman is then believed to have been involved in a crash with another car at the intersection of Marmion and Hester Avenues in Merriwa.

The woman fled from the accident and later abandoned the damaged ute at Warwick shopping centre.

Police allege she was then responsible for a car jacking when she threatened another woman in the car park at the same shopping centre, forcing the woman to hand over the keys to her car.

About half an hour later, a woman matching the offender's description was seen fleeing a bank robbery in Dianella in the stolen vehicle.

Police allege that later in the day, the same woman walked into the ANZ bank in Booragoon where she threatened staff and customers with a knife.

She fled with an undisclosed sum of money.

The woman was taken to police headquarters for questioning.