Sinn Féin leader Gerry Adams described the former secretary of state Owen Paterson as a “complete tube” in a radio interview with RTE.
Mr Adams had been asked about comments made by the former NI secretary Mr Paterson, who had suggested politicians should not have their salaries paid by the taxpayer if they do not reach agreement.
Mr Adams replied: “First of all, let me say that Owen Paterson is a complete tube.”
He did, however, add that it was “fair enough” if the government wanted to withdraw politicians’ salaries while the political deadlock continues.
Mr Paterson, the Conservative secretary of state for Northern Ireland from 2010 to 2012, said in the Commons on Tuesday that withdrawing salaries and expenses “would put pressure on the parties to come back to the talks and might crystallise minds”.
Meanwhile, Mr Paterson said that the impact of Brexit on cross-border trade has been “wholly exaggerated”.
“There is already a border, already different taxation system either side, and in my whole time in Northern Ireland – five years – nobody ever mentioned this as a problem and businesses functioned perfectly well,” he said.
“There are huge trade links between Canada and the United States and today you will have ten and a half thousand trucks that will go from Detroit into Windsor, Ontario and they hardly change gear.
“There are about 16.3 million import declarations to Canada and 92.8% of them are electronic. There is this stuff called technology that we can use on the border.”
The borders between Russia and Finland, and Pakistan and Iran, were mentioned by the Conservative MP as examples of where goods can be monitored electronically.
Mr Paterson, who served as agriculture minister in the UK government between 2012 and 2014, also said there are 1.5 million tonnes of exports going by road from the UK into the Republic of Ireland each year “and we never see them”.
He said: “What we want to establish is reciprocal free trade. It is in absolutely no one’s interest to have any sort of tariff anywhere on trade,” adding that EU states “have a massive strategic interest” in trading freely with the UK.
“There are wonderful opportunities for us all around the world,” he said, once the UK was free to negotiate independently from an EU he called the “slowest donkey in the caravan” when it came to finalising trade deals.