Barclay said the decision to strike again was hard for many members of the IRD, but it was something they had to do.
"PSA members are standing together because they want a fair deal and a better working life.
"One in four staff is paid less than $48,000, and we have heard many stories of IR workers struggling to make ends meet, relying on the tax credits they themselves administer," he said.
IRD workers had previously gone on strike in unison with employees at the Ministry of Business, Innovation and Employment (MBIE) on July 9 and July 23.
In Auckland, members will take time off from 8.30am to 12.30pm, and in all other centres they will walk off the job from 9am to 1pm.
Details of stike action around NZ:
• Whangarei: 12pm March around town
• Manukau: 11am Lunch rally at Manukau Court Square
• Takapuna: 11am Lunch rally at the square in front of Takapuna War Memorial Hall
• Penrose: 11am Lunch rally at the E tū Office
• Hamilton: 12pm placards around the block of IR building
• Te Rapa: 9am-10.30am placards at the lights on the corner of Te Rapa Straight and Garnett Ave
• Palmerston North: Rally at The Globe
• Wellington: 11am-12.30pm Q&A session at PSA House
• Christchurch: Community work at SPCA, Ronald McDonald House, Christchurch City Mission and Rannerdale War Veteran Retirement Home
• Timaru: Community work baking for Women's Refuge
• Dunedin: Community work with Presbyterian Support to help with foodbank and clearing gardens at their Manse House in Moray Place
• Members in Invercargill, Nelson, Gisborne, Napier, Greymouth and Tauranga will also walk off the job.