The DUP has said it is outraged at an attempt by Derry City Council to change the name of Londonderry Port.
The council voted last year to begin a process to change the city's name
The council has written to ask the harbour commissioners to drop London from its title.
The commissioners have discussed the matter but have decided to defer the decision until after it celebrates its 150th anniversary later this year.
The Democratic Unionists have accused Sinn Fein of attempting to strip away all things British by changing every official name from Londonderry.
However, republicans say everyone can lay claim to the name Derry, and say they are trying to create an inclusive society.
Democratic Unionist William Hay said it was a further attempt by the council and Sinn Fein in particular to alienate Protestants in the city.
"This has nothing to do with how we all manage the name," said the MLA.
"This is Sinn Fein attempting once again to strip anything British away from the city and from Northern Ireland generally.
"It is a purely sectarian argument."
Sinn Fein's Barney O'Hagan said they simply wanted to market the city with one single name.
"The term Londonderry is a political term," he said.
"The vast majority of the citizens in the city do not recognise or affiliate to it.
"With the name Derry, everyone has an a historical affiliation to it and everyone can identify with it."
Derry City Council decided last year to begin a process to change the name of the city.
A motion was passed despite angry objections by unionist councillors.
The motion said Londonderry should not be imposed as the official city name and everyone had the right to use the name they felt most comfortable with.
The local authority changed its name to Derry City Council in 1984, although the official name of the city has remained Londonderry.