The National Roads Authority (NRA) will have to spend up to €20m in repairing damage caused by recent flooding to main roads.

According to an industry source, the figure is only the tip of the iceberg as local county councils continue to assess the damage.

A spokesman for the NRA has said they have received no complaints from motorists and have had a "successful week" in clearing debris from some of Ireland's main routes.

"One of the worst hit areas in Galway saw a main motorway blocked for drivers. We managed to convince the contractors to open a new section of the M6 Galway to Ballinasloe route which is only in construction and that was a massive help for motorists this week."

Engineers in the authority were on alert this weekend in case of further flooding.

"We have been liaising closely with local authorities, and our engineers are watching to make sure the same does not happen again should there be heavy rain. We have been in the process of clearing away all debris and making over 20 routes accessible over the last week," he said.

The AA has warned drivers that despite roads being cleared, those routes that were flooded still represent a danger to motorists.

Meanwhile, assessments currently being carried out by the NRA and the Department of Transport continue and it is thought these may take "a few months", according to one source.

"We won't know the full extent of the damage until the assessors around the country have completed their reports."

The latest NRA update on the state of the country's main routes shows most major routes in Galway, Cavan and Leitrim have for the majority all reopened.

The government has also said it will provide €12m towards flood relief measures.

The Office of Public Works has spent €100m in the last five years on flood relief.