The Green Party is accusing a Crown Research Institute of trying to censor a report criticising its genetic engineering research methods.
A scientific review found that AgResearch's monitoring programme was inadequate.
The report was written for the lobby group GE-Free New Zealand by a genetics expert, Jack Heinemann.
Emails released by AgResearch show that after it received a draft last year, it asked for an extra two weeks to respond while it sought outside opinions and created a media response plan.
Greens food spokesperson Sue Kedgley says she is disturbed that the institute tried to delay criticism and discredit the scientist who wrote it.
But AgResearch says the emails show it took the report seriously.