Latest: 11.35am: Independent Senator Gerard Craughwell, who was the first senator to declare an interest in running for the Presidency, says he is very angry at Michael D Higgins’ timing.
There are just three days left in the Dail term, and county councils will take a break in August.
Senator Craughwell says now that two other Senators have expressed an interest in running, namely Joan Freeman and Padraigh O’Ceide, any nominations he thought he had are up in the air.
He also says that President Higgins cannot use public funds to run his campaign.
"There's an election from now so it's my view that he really has to step back from the use of the State's assets with respect to where he goes and what he does," he said.
" At this stage of the game, you can't have people of the country funding a campaign so we've got to start looking at how we manage to ensure that there's balance.
"If there is to be swanning around the country, then it must be at his own expense," he said.
Well now we know. President Higgins has self declared.— Senator G Craughwell (@GCraughwell) July 10, 2018
Meanwhile, Fianna Fáil leader Micheál Martin says his party will be backing Michael D Higgins, believing he is the best person for the job.
"The people of Ireland want a president who will represent them well and with distinction overseas and also then domestically, responds appropriately to key moments," he said.
"I think he's done very well, and I don't see any reason why one should oppose him for the sake of opposing him."
By Fiachra Ó Cionnaith
Michael D Higgins has confirmed he will seek re-election as president of Ireland after months of speculation over his future.
In a short statement this morning, Mr Higgins said he will be "offering myself as an independent candidate, under Article 14.4.4 of Bunreacht na hÉireann, when the ministerial order for a presidential election is made later this year".
Mr Higgins, who said the Government has been informed, is expected to answer questions on the issue at an event in Mayo later this year.
When he was elected during a hotly contested campaign in 2011, Mr Higgins said he would not seek a second term.
However, it has been widely expected in recent months he would u-turn on this promise, in part because of his high popularity among the public.
Fianna Fail leader Micheal Martin last week said his party will support Mr Higgins seeking re-election, while Fine Gael and Labour are almost certain to follow suit.
This is partially due to the fact all three parties are saving their funds for a likely general election by next summer.
However, Mr Higgins' decision still means a presidential election this autumn is increasingly likely.
Sinn Fein will discuss if it will run or support a candidate this weekend, while the Independent Alliance has said it wants to see a presidential campaign.
Independent senator Ger Craughwell, who is among three potential rival candidates who also include senators Joan Freeman and Padraig O Ceadaigh, lashed out at Mr Higgins this morning for waiting until the 11th hour to reveal his decision.
Asked if he as a former British army soldier would welcome a Sinn Fein nomination, Mr Craughwell said "a nomination is a nomination".
While Mr Higgins can nominate himself, rival candidates must either obtain the support of 20 Oireachtas members or support from local councils.