Average pay rises in collective agreements have risen to 4.1 per cent a year, driven by the largest public sector increases in at least six years, and appear set to keep climbing, according to new data.

The Department of Employment and Workplace Relations bargaining trends report on Friday showed average pay rises in public sector deals approved in the September quarter jumped from 3.7 per cent to 4.4 per cent, even as private sector deals remained steady at 3.9 per cent a year.