Northern Ireland agri-tech company Devenish has said Brexit will cost it approximately £1.7m next year.
Chief executive Richard Kennedy told BBC News NI's Inside Business programme that the lack of progress had been frustrating.
Headquartered in Belfast, Devenish has manufacturing sites and offices across the world.
Mr Kennedy said the rough calculation of costs still stands even in the event of a commercially favourable Brexit.
"That is a huge amount of money that is not going to be in the economy, not going to be available, and not going to be available for new jobs," he said.
"So for us, there is going to be costs. Now we get on with it, and it does and will dictate decisions we will make in the future, and has done already."
He added: "It's just frustrating, and more frustrating because of the fact that we can see how much can be done here [in Northern Ireland]."
The UK was due to leave the EU this Friday, 29 March.
But Prime Minister Theresa May was granted an extra two weeks to come up with a Brexit solution after talks with EU leaders.
If Mrs May can get her withdrawal deal through Parliament this week, that date will be pushed back to 22 May to give time to pass the necessary legislation.
If the prime minister can't get the deal through, the UK will have to propose a way forward by 12 April for EU leaders to consider.
Inside Business is broadcast on BBC Radio Ulster on Sundays at 1330 BST and on Mondays at 1830 BST.