Robust discussion is expected now the Bill has passed its first reading in Parliament, with concerns also raised at the speed at which it is being pushed through.
The Bill has been sent to the primary production select committee for public submissions, with the committee due to present its final report by June 1.
The Fonterra Shareholders Council has already said it would not support the Bill in its present form, saying there are "hidden" provisions that, over time, ran the risk of disintegrating the country's biggest export industry.
Yesterday, Labour's primary industries spokesman Damien O'Connor said farmers had every reason to be concerned by the Government's "unseemly haste" to push it through.
Labour was seeking changes that would prevent unlimited units being sold to outside investors without recourse to Parliament.
Fonterra shares should not be traded on the stock market in future without genuine farmer approval.
"The National Party agenda of selling our assets and farmland to the highest bidder may very well lead to the demutualisation of New Zealand's biggest co-operative ... through the changes in the Bill introduced [this week]," he said.
Federated Farmers dairy chairman Willy Leferink said the organisation was concerned to see the select committee process "truncated" to meet Fonterra's proposed Trading Among Farmers (TAF) timetable.
But Mr Carter told the Otago Daily Times yesterday the process "was not unseemly haste at all".
The Bill had been "out there and available" since January and there was still a two-month select committee process, which was "any amount of time" for submissions to be heard and the committee to make recommendations.
The timeframe had been worked through in conjunction with Fonterra, which would need a prospectus if TAF were to be implemented, and that was very difficult to do without legislation being passed.
Mr O'Connor was "doing Fonterra a disservice by raising a whole lot of inaccurate red herrings".
He suggested Mr O'Connor engage with Fonterra and recognise the "tremendous opportunities" available to the co-operative and, therefore, its shareholders if it could stabilise and expand its access to capital.
"The beneficial rights to the shares remain with Fonterra.
There is no agenda for Fonterra to demutualise.
"It's a co-operative, it's a strong co-operative and shareholders of Fonterra want it to remain a co-operative.
"This is about access to capital," he said.
Mr Leferink said there were "some big fishhooks" Federated Farmers wanted resolved.
"Farmers like me voted for the principle of a shareholders fund, but that was two years ago and was based on a concept. We also thought it was tied to the co-operative's constitution and not the DIRA itself.
"Federated Farmers strongly believes farmer-shareholders must have a clear understanding of the value proposition involved."
Legislation must not lead Fonterra's capital restructure and its shareholders must be left to determine the process without interference, he said.
The Dairy Restructuring Act (DIRA) was enacted in 2001 and allowed for the formation of Fonterra.
The Amendment Bill would ensure the Act remained a "durable platform" for the continuing growth of an efficient and innovative dairy sector. It was "critical legislation" to allow Fonterra and other dairy companies to make their contribution to the country's export economy, Mr Carter told Parliament this week.
The Bill includes embedding Fonterra's milk price governance arrangements in legislation, requiring Fonterra to publicly disclose information on its milk price setting, and introducing a milk price monitoring regime, to be undertaken by the Commerce Commission.
It also has provisions to allow TAF, which is scheduled to begin in November. These aimed to ensure TAF would deliver "deep, liquid, transparent and well-informed markets" for Fonterra shares, Mr Carter said.
The TAF supporting provisions would expire if the TAF pre-conditions had not been met by December 31 next year.
If TAF was not launched by then, or it was launched but wound up, the Bill introduced a new requirement relating to Fonterra's administratively set share price, to ensure it was set at a "fair market value".
