Workers at an Auckland call centre say their managers are timing their toilet and water breaks and that's not even why they're striking this afternoon.

Staff from Sitel's Onehunga office are unhappy their multi-national employer won't give them a pay rise.

E Tu union organiser Anita Rosentreter said on top of that, the workers also being bugged about when they'll come back to work while on sick leave, and face invasive questions about their health upon return.

"When they do return to work, they have to have one on one meetings with their managers where their managers ask questions about their health and record information about what their symptoms were and what sort of medications they were prescribed - so it's quite an invasive progress."

She said staff members are also being called at home when they are on sick leave, to try and hurry them back.

Ms Rosentreter said it's not much better even when they are at work - they're also kept on a tight leash there.

"Time away from their computers and phones is quite strictly controlled, so things like going to the toilet and going to the lunchroom to grab a drink of water is timed."

Staff at the office will step away from their phones from 2pm to 5pm.

The E Tu union said it's been trying to get a pay rise for the mainly young migrant workers for six months and Ms Rosentreter said progress is being made on sick leave policies, but the US multi-national can also afford to pay staff more.