UNIONS have threatened to use a Fair Work Commission decision on penalty rates against the Coalition in the election campaign.
The commission heard final arguments in the long-running case on Monday.
It centres on a push by employer groups to reduce pay for weekend workers from double-time loading to time-and-a-half, but a final decision is not due until June, just weeks before a possible double dissolution election.
Unions across the hospitality and retail industries are fighting the employer groups' case in an effort to preserve the higher pay rates for weekend work.
It comes as union corruption could be a key issue at the election, given laws to reinstate a Howard-era building commission could trigger the double dissolution.
But the ultimate decision on penalty rates rests with the FWC, which is independent of any government.