Welsh Church leaders have written to Prime Minister Boris Johnson to warn that a no-deal Brexit will be detrimental to the region's economy.
Church in Wales bishops said they were "compelled" to write of their concerns as Britain moves closer to the October 31 deadline for its departure from the EU with Parliament closed down and little prospect of a deal being struck with Brussels.
The bishops said that Wales was "vulnerable to particular dangers" given its reliance on farming and food production.
"The farming and food production sector, which is significantly more important to the economy than in England or the UK as a whole, is highly dependent not only on EU support, but also on ease of export to mainland Europe," they said.
They voiced particular concern over the impact on Airbus and other businesses in the tech sector "which rely on the rapid exchange of parts, personnel and expertise with our European partners, which stands to be lost, especially if we leave the EU without a deal".
However, they said that higher education, small businesses and the third sector all stand to suffer if arrangements are not put in place to replace current EU funding and partnerships.
They expressed fears that economically disadvantaged areas will be left without adequate assistance and that the UK Government will not come good on its promise to Wales for "not a penny less" than the support the region enjoys being in the EU.
The bishops said that the prospect of food and medicine shortages was "very real", in addition to concern over job losses and the strain on public services in the event that the UK crashes out of the EU without a deal or transition period.
"In the interests of reconciliation and peace, we are concerned for relationships between the countries of the United Kingdom, and for those with other European countries – with whose churches we will continue to have links," they said.
"Since our neighbours are not just those within our own shores or in immediately adjacent countries, we are concerned that leaving the EU will, in the haste to secure deals, mean trade agreements which are likely to worsen conditions for workers, downgrade environmental concerns, and make tax justice harder to implement."
They concluded by criticising the proroguing of Parliament, saying that it was important that the Government be "transparent, truthful and open" in its handling of Brexit.
"At this particular point in time, we are gravely concerned about the apparent use of parliamentary procedure to force through government decisions which have not been agreed upon, or even subjected to scrutiny, by parliament," they said.
They continued: "It is important that the government maintains the confidence and respect of the electorate. Whilst it may be true to say that governments cannot choose which public votes they abide by, even elections do not eliminate the opposition; and there can and should be creative opportunities to influence how programmes are taken forward.
"We believe that elected representatives of all political opinions have the best interests of the people at heart. We urge your government to be transparent, truthful and open in its considerations at this exceptional time."