Efforts are continuing to restore electricity and water supplies as 48,000 homes are still without water, and over 130,000 are without power following disruption from Storm Ophelia.
The ESB's Head of Corporate Affairssaid that progress at restoring power will now be slower, and priority will be given to water treatment plants and waste water treatment plants - writes rte.ie.
Speaking on RTÉ's Morning Ireland, Bernardine Maloney said estimated restoration times would be posted on Powercheck later this morning.
The majority of customers without power are in Co Cork, which was one of the areas worst affected by the storm.
Ms Maloneysaid more than 255,000 customers have had their power restored over a 36-hour period since 4pm on Monday.
She said: "As we go beyond today it's premises by premises and field by field, tree by tree - which is going to be a lot more slower progress.
"Really good progress has been made in the last 36 hours but the slower, more difficult, more rural, more isolated areas are what's remainingbeyond today really," she added.
ESB Networks said significant progress had beenmade in counties Kerry, Laois, Galway, Clare and Westmeath.
Priority is being given to the restoration of supplies for water and communications services.
Crews from Northern Ireland joined efforts last night and others from Scotland and France are expected to be drafted in on Wednesday.
Northern Ireland Electricity said about 270 homes and businesses in the Newry, Downpatrick, Bangor, Portavogie, Newtownards and Dunmurry areas were without power following Storm Ophelia.
An Post says arrangements are being made for some social welfare payments to be transferred to other post offices, as around 100 post offices remain without power.
Head of Corporate Communications Anna McHugh said information regarding the alternative arrangements will be posted online , adding that while some of the larger delivery offices were also hit by power cuts, 95% of post will be delivered today.
Power failures have also resulted in a number of wastewater treatment plants and a significant number of sewage pumping stations discharging untreated or partially treated wastewater into lakes, rivers, estuaries and the sea.
The situation is being monitored by the Environmental Protection Agency.
Irish Water's crisis management team is also monitoring the situation and will update the National Emergency Coordination Group when it meets later today.
Margaret Ashwood of Irish Water said that 48,000 people remain without water and efforts willcontinue throughout the day to restore supply.
In addition, she saidtanker deliveriesof water toareas without water would continue, and addedthat customers can log on to water.ie for tanker locations.
People in the worst affected areas, from Wexford to Skibbereen in Co Cork, have been asked to conserve water supplies as far as possible while repair work continues as reservoirs refill and pumping systems get back to full operation.
Around 110,000 Eir customers are without service, which is down fromaround 150,000 yesterday .
Eir's Director of Corporate Affairs Paul Bradley said the companyhopesto continue to makeprogress on lowering the figure throughout the day andthe biggest challenge facing repair crews was getting power restored back to exchanges and mobile sites.
Mr Bradley said they contingency plans are in place with back-up batteries and generators and the company isworking very closely with the ESB to get key locations up and running.
In a statement, Eir said the southwest and midlands continue to be the worst affected areas, and in particular Cork County.
Meanwhile, public transport services are back to normal, and primary and secondary schools reopenedafter being closed for two days.
Huge progress on the clean-up operation was reported by the National Emergency Coordination Centre yesterday.
However the group is concerned that expected bad weather forecast for this weekend might impact on restoration efforts.
As much work as possible will be done before Storm Brian arrives with wet and windy weather conditions.
Damage from Storm Opheliais estimated to cost between €500m and 800m.
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