A South Island iwi says it will no longer give its approval for the use of 1080 on the West Coast.
The Maori tribe says there is insufficient evidence that the poison is not affecting untargeted wildlife.
The deputy chair of Te Runanga o Makaawhio, Terry Scott, says kiwi are not breeding in parts of the tribe's territory and there is fear that 1080 is to blame among other concerns about use of the poison.
The TB Free West Coast Committee declined to comment on the potential implications of the iwi's decision, except to say it is worrying as the control of TB through 1080 is vital to agriculture.
The West Coast Regional Council says a 1080 drop from Hokitika to Whataroa this winter has already been granted consent.
However, it says it is likely that greater consultation, negotiation and compromise will now be needed between organisations wanting to use 1080 and iwi.