Six months after their first strike, Bunnings union members are again downing their tools in protest over roster impositions.
Staff at 29 stores began striking late on Tuesday morning.
"Bunnings is still refusing to compromise on rosters," said FIRST Union retail and finance secretary Maxine Gay.
"Under the current agreement rosters are set when both the manager and worker agree, but under Bunnings' proposal the manager will have the power to simply impose a roster on the worker," she said.
"This is going to put family time at risk. You can't plan when you have no control over your start and finish times."
The strike action will continue until members vote to end it - and the union says that will probably be when progress is made towards a settlement.
Union members first took strike action over the issue in September last year.
The Australian-owned hardware chain, which employs 3700 staff in New Zealand, has said it won't be "flagrantly chop and change team member hours or rosters".
It said last year any change to a roster would be done in full consultation with the staff member with at least four weeks advance notice.