Jackdaw, a giant gas field, was in a similar position, although Ms Fahnbulleh approved it last month.
Asked about Rosebank, Ms Fahnbulleh said that she would make the call on the evidence.
She said: “Ultimately, only I can make that decision. I really enjoy reading bits in the media, Andy’s deciding this, John’s deciding that – well, actually, only I can make that decision, and the framework is really tight.
“So even my special advisers don’t see the documents. There are only a tiny number of people in the department that have access to that. It’s a really tight process for that very reason. It’s a regulatory process. It’s not a policy process.
“You’re weighing up things like energy security, in the case of Jackdaw, its impacts on climate and other economic considerations, like jobs and growth. You have to think about the balance of all those things.
“It sits heavy for such a big controversial decision. In the end, only I can make it. And, if it is overturned by other colleagues, all that means is it’s going to be overturned in the courts. So we will do the process and we’ll do it properly.”