Supermarket giant Coles has agreed to fast-track a vote on a new workplace agreement that will pay much higher penalty rates as part of a settlement of a massive underpayment case against it.

Brisbane night-fill worker Penny Vickers wrote to the Fair Work Commission on Monday that she wanted to discontinue her action as part of a settlement agreement with Coles.

She told Fairfax Media as part of the settlement that a vote on a new Coles agreement – that pays at least the minimum rates of the award "at all times" – would be held no later than February.

"It's an excellent outcome for everyone," Ms Vickers said. "It fixes the whole problem."