The Prime Minister yesterday defended the report by Sir David Varney that ruled out a differential corporation tax rate for the province.
Speaking at his monthly press briefing in Westminster, Mr Brown insisted the review on taxation in Northern Ireland had "commanded respect" from experts who had been consulted by the government advisor.
Mr Brown also vowed to help Ulster provide a "better service" for businesses to encourage investment.
He said: "I talked to David Varney only a few days ago when I asked him to do the second review.
"I believe the first review commanded a great deal of respect from people who had been consulted.
"The consultations were wide and varied, but of course there were big issues about legality of the proposals.
"As far as Northern Ireland is concerned, I want them to get all the advantages that are all available in other parts of the island," he said.
"We will do that by providing a better service for business as they invest in Northern Ireland.
"We will provide help with research and development, we will provide training grants, we are running an investment in conference in America," said the Prime Minister.
"I believe David Varney can help the administration do what it wants to do to create new opportunities for investment."
The publication on Monday of the long-awaited report, originally due to be published in October, was met with widespread disappointment from business leaders and politicians, including Peter Robinson, the executive's finance minister.
It ruled out cutting corporation tax to 12.5% to bring it in-line with the Republic.
Sir David's report said the move would have cost almost £300m a year in lost tax receipts and would also displace existing businesses from the rest of the UK. Instead it called for improvements in skills, industrial relations, the potential for innovation and the quality of infrastructure to ensure Ulster was 'business fit'.