Transport  Infrastructure Ireland has said it has over 200,000 tonnes of salt in stock to grit roads in the bad weather.

It comes as Met Éireann issued orange and yellow snow and ice warnings for parts of the country.

An orange warning is in place for snow and ice in Cavan, Monaghan, Donegal, Leitrim, and Sligo and Mayo from this evening..

A yellow status snow-ice warning has been issued for Munster, Leinster, Galway and Roscommon.

The National Emergency Co-ordination Group for Severe Weather met today to review preparations.

Local authorities in affected area are activating severe weather plans. The Defence Forces are on standby to provide emergency assistance if required.  

The cold snap is expected to last until Friday.

Earlier, the head of forecasting at Met Éireann has warned that there will be a temporary change over the next couple of days, with a cold blast moving in.

Gerard Fleming said that there was a chance of snow showers but that temperatures should begin to rise again by the weekend.

Speaking on RTÉ’s News at One, he said the worst of the weather is expected tomorrow evening and night and warned road users to be careful on Friday morning.

"This doesn't look like it's going to be a particularly severe event but there are some risks.

"I think the worst of the times will be tomorrow evening, tomorrow night when we do expect snow showers, and as they're falling late through Thursday evening and probably freezing on Thursday night, the roads on Friday morning would be a concern, especially the roads that wouldn't be treated, which is the majority of the minor roads."

Met Éireann said very cold, wintry weather will develop tonight and affect the whole country over the coming days.

In a status yellow weather advisory, Met Éireann says: "Showers will turn wintry in many places, from Wednesday evening to Saturday, with falls of sleet and snow expected.

"The heaviest of the snow fall is most likely over Ulster, Connacht, north Leinster and west Munster and especially so on high ground."

Temperatures are set to fall below zero, while tomorrow is expected to be "bitterly cold".

Local authorities in the north west are on alert in the wake of the weather warnings and are advising drivers in the region to exercise care and allow extra time for journeys.

Donegal, Sligo and Leitrim County Councils are monitoring the situation and say that crews will be deployed to treat main routes in the region.

In Donegal the council says that people can keep up to date on the routes to be gritted by checking the inter-active winter gritting map on the council's website.

They can also view live conditions at a number of locations in the county on the website including the N15 at Bundoran and the N56 at Gaoth Dobhair.

The Road Safety Authority is advising all road users to take extra care when using the roads over the next 72 hours.

The RSA is asking road users to check local weather and traffic conditions and be aware of the conditions before setting out on a trip.

It advises drivers to clear windows and mirrors before setting out, and to avoid using hot water on windscreens as it can crack glass.

Drivers are urged to slow down, watch for black ice, and leave extra distance between you and the vehicle in front.