The firm has been appointed by developer Karl Properties to build the £75 million, 88m high, Obel Tower scheme on the banks of the River Lagan at Donegal Quay near Belfast city centre.
The Broadway Malyan-designed tower will feature 282 apartments; 3,800 sq m of office space and a restaurant on the ground floor.
The project, which may also include development of a 105 bed hotel, will take two years to build.
O’Hare and McGovern managing director Eamon O’Hare said: “We are delighted to have been appointed as contractors for such a unique development and to have the opportunity to play a part in the creation of Belfast’s premier living and work space.
"We look forward to seeing the Tower take shape over the next 24 months as part of the overall development. The Obel Tower is the second of five large contracts O’Hare and McGovern have starting in 2008 so we have challenging and exciting times ahead that will keep us busy well into the next couple of years.”