The Welsh government has accused Westminster of trying to "constrain" Wales' powers over farming and the environment.
Wales' rural affairs secretary Lesley Griffiths explained that the UK government is determined to pursue a "constitutional conflict" within the UK over Brexit.
She told delegates at the NFU Cymru Conference that the Brexit bill is an attempt to "bypass devolution".
She explained that she could not accept the EU Withdrawal Bill in its current form because it doesn't hold enough "clarity and certainty" for Welsh farmers.
Ms Griffiths also said it was "unfortunate" that Mr Gove had only attended one meeting of a Joint Ministerial Council working group on the farming since being Defra Secretary in June.
Indeed, Mr Gove has even been criticised by Scotland's rural affairs minister Fergus Ewing for missing meetings.
The Scottish government previously said the Defra secretary should be taking the concerns of Scotland's agriculture sector seriously.
Mr Gove, however, described relations with the Welsh Government as "fantastic" when the two secretaries met for the first time at the Royal Welsh Agricultural Show in July.
Agricultural system
Nevertheless, Ms Griffiths is due to meet Defra Secretary Michael Gove on Monday (6 November) for an update on Brexit talks.
Mr Gove has previously said Wales could have its own agricultural system post-Brexit.
He told the Environment Audit Committee this week that devolved nations could have their own agricultural system and funds allocated to it, but only if negotiations surrounding access to the Single Market were not infringed.
NFU Cymru President Stephen James has also urged the UK Government to avoid a ‘no deal’ Brexit scenario that could have ‘severe implications’ for Welsh farmers.
He said the Welsh agricultural industry is "fast running out of patience" with the UK government and the EU over slow Brexit talks.
The warnings coming out of the NFU Cymru Conference is likely to make Westminster reiterate the need for a unified approach to dealing with Brexit.
Last week, the First Secretary of State Damian Green warned that farm "subsidy wars" between the devolved nations of the UK would be "counterproductive" and said there should be a single market across the UK.
Mr Green said there had to be a level playing field across the UK once Britain has left the EU.
