A Brexit deal is "unlikely this week" and trade talks are "likely to move into next week", according to Ireland's foreign minister.
Simon Coveney said he was hopeful he would be "proven wrong" but played down the prospects of a breakthrough in the next few days.
He also warned of "real problems" if a deal was not struck by some time next week.
EU chief negotiator Michel Barnier is in London this week to continue negotiations on a future UK-EU relationship with his UK counterpart Lord Frost.
On Monday, Mr Barnier warned there were still three areas in which the two sides were yet to reach an agreement: Issues of governance; the maintenance of shared standards; and fishing.
With 50 days until the end of the Brexit transition period, on 31 December, Mr Coveney said the agreement of a trade deal would be "very difficult" but "doable".
"No deal is in nobody's interests," he said at an online event organised by the European Movement Ireland.
UK sources also downplayed the chances of a deal being reached this week.
It was reported on Wednesday that Brussels now sees next week's video conference summit of EU leaders as the final deadline for a draft Brexit deal.
In Westminster, the Prime Minister Boris Johnson's official spokesman said: "Time is in short supply and for our part we continue to work very hard to seek to bridge the gaps which remain between our two positions."
