A NORTH-south customs border after Brexit involving CCTV cameras and number plate technology has been dismissed as "unworkable" by nationalists.
Proposals for dealing with the border between Northern Ireland and the Republic are due to be published by the British government tomorrow.
A position paper on customs arrangements will also be released later today as ministers begin to flesh out their plans for the UK leaving the European Union.
According to reports, the British government will confirm plans for a customs border between the north and south of Ireland.
It hopes to create a 'light-touch' system through the use of CCTV cameras, automatic number plate recordings and limited customs spot checks.
It is also expected that British prime minister Theresa May will offer a 'Schengen-style' deal between Britain and Ireland to allow Irish citizens free movement in and out of the UK after Brexit.
Mrs May is due to arrive back in Downing Street on Thursday after several weeks on holiday in Europe as her government's Brexit proposals begin to emerge.
Ministers will today announce plans to seek a temporary customs association with the EU to allow a smooth transition to a new trading regime.
The UK also plans to manage the new customs border with the EU in a bid to streamline its operation and avoid a hard Irish border.
There are more than 200 roads crossing the Irish border. Critics of a technology-based solution question how movement between the jurisdictions could ever be tracked without causing major disruption.
The Irish government has made clear its position that technology alone will not resolve the issue.
Sinn Féin branded the customs border suggestions as "unworkable, bad for the economy, and not compatible with the Good Friday Agreement".
The party's Brexit spokesperson TD David Cullinane said: "The notion of a frictionless technological border has been dismissed as nonsense and impossible to deliver.
"What is clear is that Tories are prepared to use Ireland as collateral damage in their negotiations with the EU.
"What we need is a real solution that works for our economy, our communities, and delivers for all Ireland."
SDLP leader Colum Eastwood said: "Back of the envelope proposals on 'very advanced CCTV cameras' at the border don't even enter into the realm of a serious suggestion or a credible solution," he said.
"It is almost laughable that it took the British government over a year to come up with it. Anyone who knows anything about the Irish border knows its a non-runner.
"Any border must be around the island of Ireland, not across it. This is the only position which recognises our unique circumstances and it is the only position which is actually enforceable."
However, DUP Lagan Valley MP Jeffrey Donaldson insisted only the main arterial routes needed to be monitored.
"If people want to export their goods they have to go through the proper process and clearly most of the cross border roads aren't used for trade purposes, they are used on a daily basis by local people," he told the BBC.
"It is the main roads that are used for haulage and trading. So we are confident that we can deal with this in a pragmatic way."
UUP leader Robin Swann meanwhile called for Taoiseach Leo Varadkar to "dismiss the idea of a post-Brexit border in the Irish Sea once and for all".
Mr Varadkar has already said the proposal is not one he is tabling as a potential alternative, but Mr Swann called on him to go further.
The North Antrim MLA said his party would not accept such an arrangement and warned it would "tear the Belfast Agreement asunder".
