The man leading Gordon Brown's review of taxation in Northern Ireland has met Finance Minister Peter Robinson.
Senior NI politicians have held recent talks with Gordon Brown
Sir David Varney is in Northern Ireland for a series of talks with parties and business people. He will report back to the chancellor in the autumn.
The parties have been pressing Mr Brown for a cut in corporation tax, but, so far, he has resisted their demands.
Sir David said it was a "timely opportunity to assess how tax policy can support growth in the NI economy".
He added: "Over the coming months I look forward to exploring these issues further with local policy makers and businesses."
Mr Robinson said under the review, the role of corporation tax and other measures that may help the local economy grow would be considered.
"The importance of identifying all the available policy levers that can stimulate economic development in Northern Ireland cannot be overestimated," he said.
The current review of taxation is being seen as a concession to the parties in Northern Ireland. Mr Brown is due to meet business leaders on Friday.
It is expected that the chancellor will travel to the Republic of Ireland in the near future to examine its tax policy.
Irish businesses pay corporation tax at a rate of 12.5%, compared to 30% in Northern Ireland.
Sir David Varney had a long career in industry, heading Shell UK and British Gas, before becoming chairman of Revenue and Customs two years ago.
Lately, he has been acting as a senior adviser to Mr Brown.
DUP leader Ian Paisley and Sinn Fein's Martin McGuinness met Mr Brown earlier this month, to discuss a financial package for Northern Ireland, ahead of the restoration of devolved government on 8 May.
Afterwards, Mr Paisley, now Northern Ireland's first minister, said he was disappointed with the negotiations.
However, on 7 May, Mr McGuinness - now the deputy first minister - hinted that the chancellor's financial package might be increased and that talks were continuing.