Roads are currently 'blocked and treacherous' after snowfall this afternoon.
Police are advising motorists that the main roads between Limavady and Coleraine are "currently blocked as a result of snow".
"The Broad Road, Windyhill Road and Dunhill Road are currently blocked and treacherous," a PSNI spokesman said. "Motorists are advised not to travel on these roads at this time."
He added: "The Baranailt Road in Claudy is also currently closed."
News of the road closures come after an earlier yellow weather warning for ice had been issued by the Met office for Northern Ireland between 6pm today and 10am tomorrow.
"Wintry showers later on Thursday and overnight into Friday will lead to some ice, primarily on untreated surfaces but perhaps also where grit is washed off by frequent showers, said the Met Office website.
"Additionally, 1-3 cm of snow may accumulate on hills above around 100-200 m and more than 6 cm above 400 m.
"Some of the heaviest showers could produce slushy conditions even at low levels.
"Please be aware of possible tricky travel conditions."
Forecasters say the weather warning is in place for County Antrim, County Londonderry, County Fermanagh, County Armagh and County Down.