But, it was too early to say how many days that involved, and she was keeping her other job as a legal consultant, Mrs Grant said.
She was appointed by Health Minister Jonathan Coleman last week when he sacked the 11 board members because of a worsening deficit.
Mrs Grant appointed two deputies, Richard Thomson and Graham Crombie, whose daily rate is $900 a day. A third deputy will be appointed in due course.
Mrs Grant said the payments were subject to tax. Mr Thomson was one of the board members sacked by Dr Coleman. As a board member, he received $27,000 in 2013-14, while former chairman Joe Butterfield received $54,000.
''I think in the first instance it will take considerably more days than as a board member, but to try to [estimate] that at the moment is really difficult,'' Mr Thomson said.
The commissioner team plans to visit hospitals around the region in the coming weeks.
A spokeswoman for Dr Coleman said it was up to the commissioner to determine her work programme and hours.
The pay rates were worked out through a States Services Commission process.
