A poster calling for action against Evolution Mining's Puhipuhi project shows a flooded Brazilian river delta after a mining dam collapse, and likens it to the Kaipara Harbour.
The "Time for Action" poster, or panui, also makes an obscure reference to Hawke's Bay/Wairarapa iwi Ngati Kahungunu's rights to an underground aquifer.
But an Evolution Mining spokesman said the image on the poster did not relate to any of Evolution's activities - "and nor does the image appear to relate to gold mining".
The poster was put out by Ngati Hau Kuia Kaumatua and other members of the Action Co-ordination Group about a protest meeting on Sunday at Whakapara Marae.
But while the poster has been criticised for not sticking to the point, it represents the biggest modern-day call from Ngati Hau to all other Tai Tokerau hapu to join in protest action, said Tim Howard from MineWatch Northland.
Mr Howard said the message had hit home, and a large number of people had indicated they would attend on Sunday.
Mr Howard would not be drawn on what form any action might take.
He said it was important to send Evolution Mining and its backers the message that the company and mining is not welcome in Northland.
"Evolution is committed to leading environmental practices and if we are unable to identify a way to conduct our activities safely and without harm to the environment, we will not proceed," the Evolution spokesman said.
Evolution had completed and capped four drillholes at Puhipuhi to find if there are gold and silver deposits that can be safely and economically mined by underground methods, the project's chief geologist Jackie Hobbins said.
The collapse of an iron ore tailings dam in Bento Rodrigues, Brazil, in November last year - the event pictured on the poster - caused downstream flooding, 19 deaths and many injuries.
About 60 million cubic metres of waste-bearing sludge flowed into the Doce River, ruining water supplies to several cities and pouring toxic mud into the Atlantic Ocean.