Roads chiefs have ordered local authorities to mix salt with coarse sand so that supplies can be maintained for the next two weeks.
With a substantial thaw in the Midlands and East not expected until at least late next week, transport bosses warned some rural areas may not be treated over the next 48 hours.
The National Roads Authority (NRA) called for the salt-sand mix to effectively double supplies amid fears demand would not be met next week when tens of thousands of commuters attempt to get back to work.
Taoiseach Brian Cowen praised the efforts of all workers helping to keep the country moving in the hazardous weather conditions. "It is at times like these that the true sense of public service shines through. I believe it is important that these efforts are acknowledged," Mr Cowen said.
Met Eireann warned of severe frost and ice developing through the night on already compacted snow.
Five times the usual amount of salt has already been used on some roads over the last week, according to NRA spokesman Sean O'Neill. Although there are 30,000 tonnes of salt in the country Mr O'Neill said the NRA has taken the precaution of asking councils to use the 50-50 mix and conserve stocks for the next delivery in a fortnight's time.
Any hopes the weekend might bring some light relief in the capital were dashed after Dublin Bus announced its Nitelink service had been cancelled. The freeze also wreaked havoc with sporting fixtures with all the weekend's GAA matches, horse racing at Navan, Punchestown and Clonmel and some rugby cancelled.
St Stephen's Green in Dublin will be closed all weekend amid safety fears. Wicklow County Council has begun rationing water to conserve supplies.
Some parts of Leinster, including Dublin city and Kildare, experienced a slight thaw in the mid-afternoon but minor improvements on roads soon gave way to rapidly falling temperatures.
Forecasters said showers will move across the country from the west overnight, falling as snow on high ground and in inland counties.