"As soon as I knew they were using it on the Rena, I was concerned, especially because of the tide, wind, ocean currents and wave action, we don't actually know where that Corexit has ended up," Mr Zapata said.
Last week, research revealed the toxicity of Corexit increased 52-fold when combined with oil, prompting the protest this weekend.
"A lot of the surfers here have been concerned about the fact they used Corexit during the clean up of Rena and they are still prepared to use it again if there's another accident," Mr Zapata said. If the Australian Maritime Safety Authority stopped using it, and it was no longer used in Sweden and the United Kingdom, then surely New Zealand could do likewise, he said.
Mr Zapata said he was still finding oil on his surfboard two weeks ago.
"Who knows if that oil actually contains Corexit residue? No one knows."
Tauranga Mayor Stuart Crosby said he had a prior engagement at the time of the protest but he would try to attend afterward.
"I certainly do support the protesters in terms of bringing awareness to the issue and hopefully putting a bit more pressure on the agencies, like Maritime New Zealand and/or the Bay of Plenty Regional Council to not use it."
Mayor Crosby said there was a reasonable amount of community opposition to the use of Corexit and he wished protesters the best.
"I'd love to be there. They certainly have my support."
Local iwi also opposed the use of Corexit after Rena's grounding, because of a lack of research.
By 4pm yesterday, 60 people had said they would attend on the rally's Facebook page, where more information can be found.
