Mr Guy accused Mr Cunliffe of scaremongering and talking rubbish.
"I'm disappointed that he is trying to exaggerate and scare people. There are absolutely no predetermined outcomes - we want to hear the views of the public before ... any decision."
Recreational fishing lobby group Legasea has ramped up its opposition to the MPI proposals with nightly meetings in Auckland this week.
Legasea claims more than 40,000 submissions have been sent to MPI through the organisation's website.
The issue has become political at the highest level, with Prime Minister John Key saying Kiwis care more about what is happening with snapper quota than the GCSB spying bill.
Labour leader David Shearer last night told about 300 people at Bucklands Beach Yacht club he disagreed with the MPI's proposals.
"Why are they there? The commercial fishing lobby is very strong and effectively has MPI by the short and curlies," he said.
Mr Guy said he didn't attend the meeting as it would have been inappropriate so close to making a decision. The Government was represented by Whangarei MP Phil Heatley, a former Fisheries Minister.
Three members of the commercial fishing industry were also at last night's meeting. They said the fishery had vastly improved in recent years.
Mr Cunliffe said Labour had a plan for managing the fishery but he was not yet authorised to provide details.
"Number one we want to protect the sustainability of the snapper stocks," he said. "We recognise they are a key recreational fishery."
MPI has been criticised for focusing on recreational sector cuts while ignoring commercial quota and wastage. Under Labour's plan the burden for restoring fish stocks would be shared fairly between all sectors, Mr Cunliffe said. "Would we rule out cuts to commercial quota? No, we absolutely wouldn't."
He questioned the accuracy of the science put forth by MPI, saying it was "not yet fully accurate".
"Getting the wastage down, particularly of juveniles by commercial fishers, is crucial," he said.
Mr Guy said two studies on the level of the recreational catch had cost $3 million and the results had been peer-reviewed internationally.
"Most people, when they hear the full range of options, are quite supportive of what MPI are consulting on," the minister said.
Proposed rule changes
Option 1
* Reduces the recreational catch from an estimated 3365 tonnes to 2550 and leaves the commercial catch at 4500 tonnes.
Option 2
* Reduces the recreational catch to 2730 tonnes and increases the commercial quota to 4830 tonnes.
Option 3
* Reduces the recreational catch to 2370 tonnes and reduces the commercial quota to 4180 tonnes.
* All three options involve limiting the recreational catch by reducing the daily bag limit, increasing the minimum size, or both.
* Proposed changes range from leaving the minimum size at 27cm while reducing the bag limit to three, to increasing the minimum size to 36cm while leaving the bag limit at nine.