The National Party is being called on to state its position on the labelling of genetically modified food in trade talks if it is re-elected.
A new poll commissioned by anti-GE group the Sustainability Council has found 83% support for compulsory labelling.
In the past, the United States government has highlighted labelling as a barrier to trade.
Sustainability Council spokesperson Simon Terry says the National Party must say whether the labelling law is up for negotiation in the TransPacific Partnership trade talks, which includes the US.
Earlier this week the National Party leader, John Key, said he did not expect changes to rules governing field trials of genetically modified foods as a result of the talks.
Mr Terry says the comments did not address the issue of labelling.
Labour Party trade spokesperson Maryan Street says there are good reasons why labelling laws should be retained.
"Whether it's country of origin labelling or GM component labelling, all of those sorts of issues to do with traceability and transparency for consumer choice are really becoming increasingly understood and more strongly felt by New Zealanders," she says.