The Forest Owners Association has apologised and said the industry is committed to cleaning the beach and owners will pay for it, not ratepayers.
The beach in Uawa is strewn with logs and debris from forestry operations up in the hills.
The slash washed onto the beach over the weekend after a metre of rain fell in 24 hours.
Forest Owners Association president Phil Taylor said: "On behalf of the forest industry ... I unreservedly apologise to the community for the debris on the beach. They acknowledge it is unacceptable. I can assure the community on the East Coast that the forest industry is committed to cleaning the beach up in conjunction with GDC (Gisborne District Council) ... that planning is underway."
He told RNZ's Morning Report logs could continue washing up for years.
"The reality is this is likely to continue but in a reducing way for a number of months and years."
Taylor said working with council would not mean the clean up would be funded by ratepayers.
"The forest owners will be shouldering that burden."
Work had been ongoing since the storm of 2018, but it was a high-risk job to remove the logs and debris from the ravines, Taylor said.
He could not reassure the community that it would not happen again.
"What I can tell the community is that the forestry companies unreservedly apologise for this and they are doing their utmost to ensure the impacts are reduced. Where it does to continue to come out of the forests - which should be on a much-reduced level - they commit to clean it up."
More rain could cause even more problems for the region and Tairāwhiti locals are preparing for a second storm.
Tolaga Bay Civil Defence emergency manager Greg Shelton told RNZ's Morning Report the beach was in bad shape.
"We've got the beach covered, but in 2018 we had a lot of logs that took a lot more to burn - they were greener. This time we haven't got the problem of big logs, we've got more of the slash."
He said they would get around to burning that in November.
"We've been lucky ... all the slash and silt stayed in the waterways. Apart from road closures, there have been no infrastructure, no houses, fences, been damaged."
It was fine this morning, he said but would be alert for the weather at midday.