Dozens of demonstrators are said to be protesting against deep sea oil exploration, outside a National Party regional conference.
They are opposed to the Brazilian oil company Petrobras surveying in New Zealand waters.
The exploration in the Raukumara Basin has been met with protests by Greenpeace and local iwi since it started.
The protesters are at the National Party's Central North Island conference in Gisborne which John Key is attending.
One protester, Ani Pahuru-Huriwai, says there are about 80 people at the rally.
"We want to tell John Key and other politicians that are here to the fact we want them to stop extraction. We want the Raukumara Ranges and the Raukumara Basin to be off-limit to multi-national companies who wish to explore for petroleum gas and minerals."
Ms Pahuru-Huriwai says there may be further protests on Sunday.