President Barack Obama has come under fire over his trip for the G8 summit in Ireland which is estimated to have cost U.S. taxpayers more than $5.2million.

The Obama family touched down on Air Force One in Belfast on Monday morning, amidst the biggest security operation ever mounted in Northern Ireland.

After a morning address at the Waterfront Hall in Belfast City, President Obama joined other world leaders at the G8 conference in Co. Fermanagh. Michelle and daughters Malia, 14, and Sasha, 12, headed to the Republic for a series of engagements.

The first lady and her two daughters stayed at a $3,300-per-night hotel suite at the five-star Shelbourne Hotel where her entourage has booked out 30 rooms in the five-star accommodation.

The Shelbourne Hotel is one of the city’s oldest, overlooking Dublin’s famous park St Stephen's Green.

Although the White House has not released specific costing on the trip, the estimate is based on the President’s one day trip to Ireland in 2011 which tallied a $2.6million bill, reports the Daily Mail.

The two day trip is likely to cost double that, considering the family have been split up. The first family’s three-nation trip to Africa at the end of this month is expected to cost up to $100 million.