Scottish food producers have sent a letter warning UK Trade Secretary Liz Truss about the way trade deals are being negotiated.
The 14 companies and trade bodies have expressed concern about the free trade agreement being developed with Australia.
They say they are disconnected from talks which have been "rushed".
Ms Truss has insisted British farmers have nothing to fear and an "awful lot to gain" from a deal with Australia.
She suggested a 5% whisky tariff may be scrapped in the first agreement drawn up from scratch since the UK left the EU.
In the letter, Scotland's main farming, fishing and processor groups said there was no collaboration between Whitehall and the industry.
They said the deal struck at Christmas with the European Union left firms to face costly consequences, and they warned that could happen again when new deals are "hurried through" with Australia and then other major exporters of farm produce.
Whitehall ministers have sought to reassure producers that there will be safeguards, and new trade deals will open up opportunities to sell exports beyond Europe.
But critics of the proposed agreement fear the zero tariffs, zero quotas deal that the government in Canberra is demanding would see British farmers and businesses undercut by Australian rivals.
'A bad precedent'
Scotland's food and drink sector suggested it could set a bad precedent for future deals.
The letter, with signatories including the chief executives of the National Farmers' Union Scotland, the Scottish Seafood Association and Scotland Food & Drink, said: "We recognise the UK government's desire to move quickly to create new opportunities with nations beyond the EU.
"However we are concerned that the pace of these negotiations, particularly the free trade agreement with Australia, is too quick and denying the opportunity for appropriate scrutiny and consultation.
"Trade deals are complex and markets are sensitive; the impact of the Brexit deal has demonstrated this.
"The risks here are enormous for the whole food and drink supply chain and, in the absence of any formal impact assessment to suggest the contrary, we remain hugely concerned at the impact on sensitive sectors of our industry."
It added: "We welcome an ambitious trade policy if it will open new opportunities for our producers."
It said that the EU market remains the most important export market, with it being the destination of two-thirds of all food exports.
Scotland Food & Drink chief executive James Withers said: "As a food and farming industry we want to be ambitious for global trade. The future of our sector relies on it, and international sales of Scottish food and drink are already worth over £6bn in a normal trading year.
"However, if we rush trade deals through, without any serious scrutiny and no engagement with industry and other experts, we can harm businesses, communities, the environment and the UK's international reputation."
'All voices are heard'
A Department for International Trade spokesman said: "We seek a wide range of views before, during and after negotiations to ensure all voices are heard, and consult widely across the country before we launch talks, including extensive engagement with Scotland, Wales and Northern Ireland.
"We will only sign deals that work for all parts of the United Kingdom, including any potential deal with Australia.
"Our Exports Minister was in Scotland last week to champion the benefits of the Australia FTA, highlighting how a tariff reduction would benefit iconic goods like Scotch whisky.
"Any deal we sign will include protections for the agriculture industry and will not undercut UK farmers or compromise our high standards."