The Council of Trade Unions is campaigning for sick leave to be doubled, from five to 10 days per year, and says it will benefit all of New Zealand.
The union said Covid-19 had shown New Zealanders how important it was to stay home when employees were sick, but five days was simply not enough.
Its president, Richard Wagstaff, told Morning Report that many people felt they could not afford to take days off after they had used their sick leave.
"It's apparent to everyone, particularly this year, that we don't want people going to work when they're sick - and if we don't have enough sick leave, that's exactly what will happen."