Wales' first minister has criticised Boris Johnson's plan to set a deadline for striking a trade deal with the EU as "dangerous and misleading".
It featured in the Queen's Speech which follows the Tories' election victory.
Mark Drakeford said it would not end "this sorry Brexit saga" while Plaid Cymru MP Liz Saville Roberts complained there was no mention of post-Brexit funding promised for Wales.
Welsh Tory leader Paul Davies welcomed "an ambitious plan for the whole UK".
In the programme for action presented to Parliament on Thursday, the returning Conservative government's stated priority was to ensure the UK's departure from the EU on 31 January, with legislation to ban any moves to extend the transition period beyond December 2020.
Other bills will set out post-Brexit arrangements on farming, fishing, financial services and other sectors.
A "points-based immigration system" is intended to allow the UK to welcome skilled workers, with a new visa aimed at fast-tracking entry for health professionals.
A commitment to an extra £34bn NHS funding in England will also be enshrined in law.
Giving his reaction, the Welsh Labour leader Mr Drakeford said: "The PM's self-imposed ticking Brexit clock is dangerous and misleading.
"He is upping the ante on a no-deal Brexit by the end of 2020, which would be catastrophic for Wales. It would also not spell the end of this sorry Brexit saga.
On the subject of health, Mr Drakeford said: "We have long called for an increase in funding to protect our precious NHS so today's commitments are welcome.
"But the PM must now put his money where his mouth is so we can start the process of recovery from the damage caused from 10 years of austerity."
Monmouth MP David TC Davies, the new Wales Office Minister, defended the decision to set a deadline on Brexit trade talks.
"Obviously at some point if the European Union don't want to play the game then we're going to leave anyway, that's what the public want," he said.
"It's what the public have voted for now three times. - once in a referendum, secondly in 2017 [at a general election] and once again, very, very firmly, in the election just now."
Ms Saville Roberts, who leads Plaid Cymru at Westminster, said the second Queen's Speech in little over two months showed "complete apathy" for Wales.
"This Queen's Speech has no new ideas and fails to deliver the funding that was promised to Wales during the Brexit referendum," she said.
"We don't even know what will replace the funding we have received from Europe for decades."
However, Paul Davies, who leads the Conservative group in the Welsh Assembly, claimed the prime minister had "stuck to his guns" and would "get Brexit done" to "increase the prosperity and opportunity for all in the UK".
Referring to the latest A&E waiting times for Wales published earlier, Mr Davies claimed the Labour Welsh Government had "failed the people of Wales", with four out of seven health boards subject to some form of government intervention.
He said the Conservative group would urge Labour ministers to spend the extra £1.9bn it would receive from the UK government due to health spending increases in England on "improving outcomes for Welsh patients".
Analysis by Paul Martin, BBC Wales political correspondent
This week the Welsh Government increased the budgets of all of its departments for the first time in a decade.
It could do that because of the extra cash it's getting as a result of the UK Government increasing spending.
Both the Conservative manifesto and today's Queen's Speech reinforce that direction of travel.
It's significant financially and politically after a decade of spending cuts.
Analysis of the Conservative manifesto by the Wales Governance Centre found that the Welsh Government budget will increase by 8% by 2023/24, taking it above what it was in 2010/11.
But the demands of the NHS may mean the impact of that money isn't felt particularly strongly elsewhere.
The key dynamic in Cardiff Bay over that period has been Labour ministers defending their record on public services by blaming Conservatives (and Lib Dems for a while) for cutting the money they have to run things.
To some degree that ends now, and the Welsh Labour line, as articulated by Mark Drakeford today, becomes about now trying to "recover" from the "damage" cause by austerity.
The extent to which voters accept that logic will be one of the key factors as the performance of the Welsh NHS, schools and local government come into sharp focus in the run-up to the next Senedd election in 2021.