The National Emergency Coordination Committee has issued a red alert, ordering everyone in the provinces of Munster and Leinster to stay indoors from 4pm on Thursday until noon on Friday.
He told BBC Scotland's John Beattie: "It couldn't be clearer, couldn't be simpler - don't travel, avoid travel, because if you do you will not only be disrupted but, as I said, potentially putting yourself and others into danger".
The majority of the United Kingdom that has not been hit by the red warning is now on yellow (severe weather) or amber (bad weather which could disrupt plans and has a potential risk to life and property) warnings.
Travel and public transport disruption is expected, and hundreds of schools across the country have already been closed.
Midlothian's weather is now so severe that there is a "likely" risk to life, after the Met Office upgraded their weather warnings for snow to Red, the highest possible rating.
Strengthening winds caused blizzards and drifting snow in some parts, bringing roads to a standstill and leaving commuters facing more travel disruption.
"Long interruptions to power supplies and other utilities are very likely to occur, along with damage to trees and other structures due to heavy snow or ice".
Meanwhile, the Irish Republic was put under red alert at 11pm on Wednesday as it was hit by the worst snow in 35 years, with the warning set to run until 3pm on Friday.
Motorists on the M80 near Glasgow reported being stuck for up to 13 hours, with some spending the night in their cars, and others abandoning their vehicles on the motorway.
An amber snow warning is in place for the North East and Scotland from 6am on Wednesday to 12pm on Thursday, with up to 40cm of snow expected to fall during that period.
MONMOUTHSHIRE should prepare itself for more snow with the Met Office issuing an amber warning for the next two days.
- Hundreds of schools were forced to close, including more than 125 in North Yorkshire and more than 330 across Kent, giving thousands of children a second snow day.
The chief forecaster at the Met Office said: "Widespread snow is expected to develop through Thursday afternoon and evening".
The extreme weather has also seen NHS Greater Glasgow and Clyde cancel all non-essential operations and outpatient appointments on Thursday.
Snow showers are likely overnight from around 1am until around 7am on Saturday, March 3.
The Met Office said: "Very strong easterly winds will affect high ground in Northern England and Wales, with some powerful gusts also at lower levels to the west of the hills".