Australian women earn just 3.9 per cent less than men for the same work when factors like experience and education are taken into account, shows US research that suggests the gender pay gap isn't as big as previously thought.

A survey of five countries has found when women's average base salaries are compared with men's base figures, there is a gender pay gap of 17.3 per cent in Australia, 24.1 per cent in the US and 22.9 per cent in Britain.