Beekeepers could well be left responsible paying for a biosecurity breach they had no opportunity to prevent, he said.
He cited the Government's intention to allow Australian honey into the country, which had the potential to bring in three new pests and diseases, Paul said.
"We don't have any concerns that consumers would stop buying New Zealand honey.
"What we are concerned about are the chances of a serious biosecurity breach if Australian honey is allowed in. Who's going to pay for that?"
The Government could not on the one hand allow a new product into the country and then expect the industry to pay the costs if something went wrong, he said.
The benefit of the GIA was that beekeepers would at least get to sit around the table and talk with the Ministry for Primary Industries (MPI), he said.
"There's sufficient benefit to warrant signing up. It would be foolish to write it off right now.
"If we're not a signatory and something happens, we just won't have the chance to talk with MPI about how to deal with it."
Paul said he hoped discussions now with the MPI would lead to a fair cost-sharing agreement.
MPI said the GIA, planned to start formally on July 1, 2013, would give primary industries a better say in biosecurity preparedness and response activities.
A Joint Working Group, made up of industry members and the MPI, was currently in discussions over what the agreement would look like and how the cost-sharing would work.
The working group was expected to produce a draft Deed of Agreement for industry bodies to comment on later this year, with industry members to eventually vote on whether to sign up.