Anti genetic engineering lobbyists are concerned about a proposed new national environmental standard for plantations which is going through its third round of consultation.
The government said a national standard would simplify rules and save the forestry industry millions in compliance costs.
Forest owners are keen on having a national standard. They say having to comply with different rules set by local councils makes it difficult to manage forests in more than one region, or blocks that straddle council boundaries.
The proposed new standard would make forestry a permitted activity on land of low erosion risk.
But resource consents would be needed for high risk land to cover activities such as forest roading and harvesting.
However, GE Free New Zealand is concerned that planting genetically modified trees would also be a permitted activity under the new rules.
And Green MP Steffan Browning said that would cut across councils' rights to include precautionary statements about genetic engineering in their district or regional plans; as some currently do.
"The proposed national environment standard for plantation forestry, in terms of hazardous substances and new organisms, says that, should the EPA (Environmental Protection Authority) approve genetically engineered trees fit for the environment, it would be a permitted activity under the RMA.
"So that means that all council plans, in the way that we're looking at it, would have to allow the genetically engineered trees in their regions. It doesn't give the councils the ability to put in conditions, which would be a controlled activity, or to even say no in a precautionary way or to protect the economy of that region because it wants to be GE free, and that would need to be discretionary in the plan."
The Primary Industries Ministry is holding consultation meetings around the country this month, and the Government aims to pass legislation to put the national plantation forestry standard into effect next year.