The opening of Concourse D is the "result of a $1.2 billion investment to enhance service and boost capacity for the more than 70 international airlines," Dubai Airports said in a statement.
British Airways was the first airline to use the new concourse, connected by train to Terminal 1.
Dubai airport 2015 traffic up 10.7 per cent, world's busiest
"Today we also announce our 2016 forecast which projects 85 million passengers will visit Dubai International this year," said Dubai Airports CEO Paul Griffiths.
Dubai International said it remained the world's busiest airport for international travel in 2015 with more than 78 million passengers passing through.
Dubai first announced it had overtaken Britain's Heathrow as the world's busiest airport for international passengers last year, after 70.4 million international travellers passed through in 2014.
Situated on transcontinental air routes, Dubai is one of several Gulf-based airports to experience prodigious growth in recent years.
Messi passport video lands Dubai policeman in court
Around 100 airlines fly to more than 240 destinations from the international hub, which is also home to carrier Emirates.
Dubai's second airport, Al-Maktoum International, opened in 2013 and will be capable of receiving 120 million passengers a year once fully operational.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ