Workers at Westpac began negotiations on Tuesday to try to have their pay rises inflation-proofed.
The bank workers' union, Finsec, wants a 5% pay rise and a guarantee from the bank to top up wages to match future inflation rates.
Finsec spokesperson Andrew Campbell says inflation-proofing wages would cost Westpac 3% of the $125 million profit it has made so far this year.
The Treasury has predicted inflation will rise to 5.9% next year.
An economist from Economics New Zealand, Donal Curtin, says inflation-proofing was more common in the 1960s and 1970s when inflation rates were soaring above 10%.
Next year's forecast inflation rate is likely to be a one off, he says, due to the impact of a GST rise and the Emissions Trading Scheme.