The EU is to set out proposals later to address the row about trade in Northern Ireland.
The UK wants to change the deal struck as part of the Brexit process to allow goods to circulate more freely between Great Britain and Northern Ireland.
It says the current rules impose too many barriers to the sale of chilled meats and other products.
The EU's proposals, which it calls far-reaching, are expected to involve reduced checks on goods and medicines.
At the start of the year, a new post-Brexit arrangement - known as the Northern Ireland Protocol - was introduced to help prevent checks along the border between Northern Ireland and the Republic of Ireland.
It involves keeping Northern Ireland in the EU's single market for goods - but this, in turn, creates a new trade border with Great Britain. Unionists say this undermines their place in the UK.