Today is expected to be the biggest online shopping day of the year, as Irish customers plan ahead for Christmas.

Known as ‘Cyber Monday’, the first Monday in December has become the busiest online shopping day annually all over the world.

It is thought to arise as a result of the last payday before Christmas falling on the previous Friday, and a weekend spent browsing the shops before buying from home.

Irish shoppers are expected to spend an estimated €500 million on online purchases between now and mid-December, according to eMark, an identification symbol for Irish owned and operated ecommerce sites.

Michael McCormack of eMark estimates that three-quarters of this spend will go to overseas companies.

"We know that Cyber Monday is likely to be the busiest online shopping day of the year and therefore eMark are appealing to Irish online shoppers to consciously look out for retailers who support businesses and jobs in Ireland, " he said.