That's a hell of a lot of zone one tickets. Or a typical Toorak mortgage.

A shocked Melbourne commuter has checked the balance on their myki card to find they owe the eye-watering sum of $2,684,350.

The receipt given to Sarah Coles showing a debt of $2,684,350. Credit:Twitter

Sarah Coles was trying to top up her myki with $5 at the North Melbourne station ticket office at around 5.10pm on Thursday when a staff member pointed out the enormous negative balance.

She said the staff member initially seemed to believe that the back-breaking debt was real before asking her to call myki and sort out the problem. She was given a receipt as a reference.