Welsh businesses and ports are not yet ready for the end of the Brexit transition phase in 50 days' time, a Welsh minister has said.
Labour's Jeremy Miles has asked firms to urgently look at what they need to do by 31 December.
He urged UK ministers to "support jobs" by not ending the transition period without a trade deal with the EU.
But Conservative Welsh Secretary Simon Hart said that "by and large people are getting ready".
On Wednesday the Welsh Government published its plan for the end of the transition period.
The report says a "Crisis Intervention Scheme' may be needed to support Welsh meat exporters if no deal on UK-EU trade is struck.
"Such a scheme could potentially be of a substantial scale and would require cross-UK collaboration and additional UK Government financial support to be provided to the Welsh Government to deliver," the document says.
It also warns of "potential for major disruption to international trade (particularly, but not only, with the EU) impacting on exporting businesses, import supply chains and inward investment which all in turn could risk the sustainability of some businesses and negatively impact on jobs and wages".In the meantime Mr Miles, Welsh minister for European transition, has urged people to look at how their business or family could be affected by the end of the transition period and take steps to prepare.
He called on the UK Government to "take responsibility and act with us" on areas it is responsible for.
The transition phase, until the 31 December, allows the UK to trade with the European Unions as if it were a member, with the United Kingdom following EU rules and regulations.
The UK is currently negotiating a trade deal with the EU, but there are sticking points on issues such as fishing rights and business competition rules.
The prime minister has insisted the United Kingdom is "very well prepared" to move on if the two parties cannot agree a deal.
Without a trade deal, the UK would trade with the EU on World Trade Organisation terms - meaning higher taxes would be imposed on products being imported and exported. A lamb producer, whose farm spans the Wales-England border south of Wrexham, is concerned about the impact of these tariffs if the UK has to sell its lamb to the EU without a trade deal.
Helen Roberts, who is also development officer of the National Sheep Association Cymru, said a deal would offer farmers security.
"We've taken the decision to carry on putting the ram out, and producing next year's crop, and we'll have to take the consequences of what a no deal might bring for us next year, which could possibly be a cut in income of up to 30%," she said.
How ready are businesses?
Mr Miles said it was difficult to mitigate all the impacts of the transition period ending but businesses needed the "certainty" of knowing whether a deal would be agreed or not.
He said: "These are big challenges and the message from us isn't 'everything will be fine', but everyone needs to make sure they're aware of the impact on them and take the appropriate steps in the short period we have left."
However Mr Hart said businesses should be aware that deals "by and large go to the wire".
He added: "I don't buy the argument that somehow the fact this hasn't been settled by now comes as a surprise. That's not how substantial negotiations like this work."
What about Welsh ports?
Mr Miles said that while some of the responsibilities of preparing Welsh ports were Welsh Government responsibilities, checks on the border from 1 January would be a UK government responsibility.
"We need to make sure that businesses, exporters, hauliers, the port companies are all prepared for that and the infrastructure is in place to deal with it," he said.
Mr Miles added there had not been "as much engagement as we should have" over the Welsh Government having more involvement in the discussions.
However Mr Hart said there "has been proper engagement".
"The infrastructure plans around Holyhead are well advanced," he said. "There has been discussion around the precise location of a site, that involves local authorities and others.
"I'm confident we can meet the deadlines by June or July next year so any disruption is absolutely minimised.
"That does require UK and Welsh Government collaboration - that element has been quite positive."
No deal 'a political choice'
Mr Miles said it would be "grossly irresponsible" of the UK government to fail to agree a trade deal with the EU.
"If the UK leaves the transition period with a weak deal or no deal at all - that will be a matter of political choice for the UK government.
"We are asking the UK government to make the right choices to support jobs and livelihoods in Wales, to give people the clarity and the certainty that they are crying out for what will happen at the end of December."
But Mr Hart said that if no deal was agreed then Wales could "weather that storm and come out stronger the other side" and ruled out an extension of the transition period.
"We made a commitment in our manifesto to deliver on the outcome of that referendum, that's precisely what we are doing - no ifs no buts."