A distraught woman has spoken of the moment she managed to grab a pair of scissors from her attacker in a terrifying carjacking in Melbourne's south-east.

Anna, 49, told radio station 3AW that she was in her car at Landcox Park, Brighton East when she was approached by a man.

"Before I could think, he opened the door really forcefully, he had a pair of scissors at my head, and said very loudly 'get out of the car'," she said.

"He pulled me physically out of the car and I must have instinctively tried to protect my head, and I grabbed the scissors from him."