Irish people living in Britain have been urged to check if they are eligible to vote in the upcoming Brexit referendum.

Irish citizens resident in the UK may be entitled to vote on June 23rd, but the deadline to add yourself to the register is midnight tonight.

Noelle O'Connell, from the European Movement Ireland, encouraged people to register regardless of what way they intend to vote. 

"This decision is certainly crucial and it affects both our islands," she said.

"To that extent, European Movement Ireland is urging all eligible Irish voters in the UK and the people living here in Ireland to register online to vote by midnight tonight, June 7th.

"And no matter how people decide to vote, it is absolutely crucial and vital that they have their say on June 23rd."

Three separate opinion polls have put the campaign to leave the European Union in the lead just two and half weeks ahead of the referendum.

Meanwhile, a new PWC survey of Irish CEOs shows that while more than 90% say that a Brexit is the top threat to business growth, only 10% have carried out any serious planning for its potential impact.

Irish citizens aged 18 or over who live in the UK, Irish citizens born in Northern Ireland but are now living overseas, and Irish citizens currently overseas but who have been registered to vote in Northern Ireland in the past 15 years are all eligible to vote.