The ACCC has launched the action alleging 10 breaches of the Trade Practices Act.
Cabcharge faces penalties of $10 million per contravention plus a pecuniary penalty of 10% of its annual turnover for each contravention.
Cabcharge's revenue for the last financial year was $173 million.
That's a total potential penalty of $273 million.
A spokeswoman for Cabcharge Tracey Cain said: "Cabcharge always behaves appropriately".
Consumer Watch spokesman Paul Tully says: "We'll see".
PAUL TULLY: email@example.com
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