Site manager Steve Courtney urged anyone who could get to the beach to do so.
"I think people are going back to work and people are telling them it's clean. If they're being told they can walk on the beaches, they might think, 'Why do we have to clean them?'
"The problem is not going away and it's not going to go away.''
Volunteers at the beach in the afternoon were frustrated but realised the importance of their efforts.
Papamoa resident Debbie Keane said it was her sixth day volunteering and she wished more people would join her.
Steve Palmer, also from Papamoa, has been volunteering every day since the first day volunteers were called and plans to stick at it.
"It seem frustrating just going over the same patch of sand [but] you're still doing something. We're winning, I think.''
He realised many people had busy lives but urged others to help when they could.
"Even doing two hours or three hours is better than nothing. Anyone who can get down here, they're champions.''
Rena volunteer co-ordinator Pim de Monchy said there were almost 7000 registered volunteers and about 150 new recruits were accepted every day.
He said volunteers could show up on the day without being previously registered.