Sinn Fein has been accused of attempting to intimidate major retailers and shop owners for stocking products made in Israel on their shelves.
Superstore bosses and shops have been asked to produce lists of the goods they sell from Israel "or the occupied countries".
A letter to store bosses warned the continued sales are giving "financial support, succour and legitimacy" to Israel's "unchecked and escalating violations of Palestinian human rights."
It was sent by SF Newry and Mourne Mayor Daire Hughes who also suggested retailers could use "alternative" suppliers "if you feel it would be prudent".
Mr Hughes has also come under attack for sending the letter to stores like Marks and Spencer in Newry using official headed council notepaper.
The DUP's Jim Wells said some retailers are seeing this as a clear attempt to intimidate them and that Mr Hughes should resign.
"This is a veiled threat that shops who do not do what Sinn Fein wants will be outed," he said.
"People have not forgotten Sinn Fein's ties with the IRA in the past, when the Provisionals trained with the Palestine Liberation Organisation and, of course, that they blew up shops not just in Newry but across Northern Ireland.
"I find it appalling that at the same time as the synagogue in Belfast is being attacked, we have politicians who are supposed to be civic leaders upping the ante by sending letters such as this."
The South Down MLA also argued it was a "bit rich" for Sinn Fein to be lecturing retailers about human rights issues.
"Shopkeepers have a right to stock whatever it is they think people want and customers to buy them without interference from Sinn Fein or any political party."
Ukip Newry and Mourne councillor Henry Reilly also accused the mayor of abusing his office.
"The mayor is not allowed to do anything political during his period in office and he has done this as mayor, he has not sought the support of the rest of the council. He has so compromised his position as a civic leader that he cannot continue in office," he said.
In his letter, Mayor Hughes said: "I would request a list of products you stock from Israel or the occupied countries."
Responding to Mr Wills, Mr Hughes added: "(His) comments are hardly surprising given the fact his party recently established a Friends of Israel group at Stormont." Newry's Chamber of Trade and Commerce said: "It is up to individual retailers to decide if they would like to consider the proposal." And Marks and Spencer, which was among the outlets which received the letter last week, said: "We are an apolitical organisation. We do not align ourselves with any nation or state.
"We do not take any products from the occupied territories – we only source from areas that we can visit safely."