Rooms have been upgraded with new framed MyBed units, personal espresso machines, LCD televisions and Bose sound systems in suites.
The hotel was well placed to take advantage of the Wynyard Quarter expansion where about $1 billion of private investment is being sought, he said.
The property became a Sofitel last February and about 50,000 people had stayed there since then, de Graaf said.
The hotel is the second in New Zealand for Sofitel, which also operates in Queenstown.
A third site was planned for 2014 when a new Wellington property would open, de Graaf said.
Auckland's Sofitel is owned by multimillionaire low-profile Auckland family the Pandeys who are based on Queen St but have hotels around the world.