Plaid Cymru MS Mabon ap Gwynfor has said that the new Australia trade deal will mean the "end of Welsh farming as we know it".
The party's spokesperson on Housing and Planning said that the deal will also lead to
the annihilation of the Welsh language and the country's rural culture.
43% of workers in the country's agricultural industry speak Welsh— which is a higher percentage than in any other sector.
The MS for Dwyfor Meirionnydd also sarcastically congratulated the UK Government on the trade deal which he said will "lead to an economic growth of 0.2%, which will naturally benefit the wealthiest."
He added: "Correction: 0.02%. Even better."
Things that make Wales 'Wales'" are "at stake"
The First Minister Mark Drakeford has previously warned that the "things that make Wales 'Wales'" are "at stake" in the row over an Australian tariff-free trade deal.
Speaking on BBC Radio 4's Today programme, Drakeford expressed his concerns about the impact that such a deal would have on "the future of our communities."
Drakeford also said that the country's "Welsh-speaking heartlands", in particular, would be threatened by the deal.