The two young victims were attacked on Saturday and Sunday mornings in Ainslie and Civic.

ACT Policing say the assaults were unrelated but have urged people to be ''alert and aware''.

A 22-year-old woman was seized and assaulted at 3.15 Saturday morning while walking along Sherbrooke Street in Ainslie.

The assault continued for several minutes before she managed to lash out at the male attacker and break free.

She fled, with the attacker pursuing her a short distance.

North District acting Superintendent Erin Pobar said several people may have seen or spoken to the victim shortly before the attack occurred.

The victim told police a middle-aged man with tattooed arms rode past on his bicycle and gave her directions.

The 22-year-old also spoke to three men travelling in a small white car who offered her a lift near North Ainslie Primary.

Two females walked past the victim near the Ainslie Fire Station on the corner of Wakefield Avenue and Limestone Avenue, near the Ainslie Football Club.

Acting Superintendent Pobar urged these people to contact police.

''When you're out and about at that time of the morning you might recall seeing a female alone walking down the street also.''

The attacker is described as 183cm tall, athletically built with short brown hair. At the time of the attack he was wearing grey tracksuit pants, a tight short-sleeved T-shirt and white slip-on tennis shoes.

The next day a 20-year-old woman was sexually assaulted at knifepoint in a car park of London Circuit in Civic.

The victim was attacked as she climbed out of her car.

The offender was described as being 183cm tall, in his late 20s, light-skinned and muscular. His head was mostly shaved, with a light-brown or blond curly ponytail. He had a tribal style tattoo circling his left upper arm.

Acting Superintendent Pobar advised Canberrans to be aware of their surroundings.

''When people are out at night we recommend that they wherever possible stay with friends and avoid going into situations and places that make them feel unsafe, such as walking through a dark car park alone or through a park,'' she said.

Anyone with information on either assault should contact Crime Stoppers on 1800333000.