The North's Minister for Finance, Peter Robinson, has dismissed a proposal by the chairman of Ulster Bank Group for a merger of the Industrial Development Agency (IDA) with its Northern counterpart, Invest Northern Ireland, saying it would be "moving along an agenda that is very much a united Ireland agenda".

Ulster Bank Group chairman Dr Alan Gillespie proposed earlier this week in an article in The Irish Times that the two job-creating agencies should be merged "to promote an all-island economy through a single joined-up effective agency".

Speaking after an Irish Taxation Institute briefing in Dublin yesterday, Mr Robinson said the distinctions between the North and the Republic made it "impractical to go forward with that kind of proposal".

"I am not going to hide the fact there would be major political issues involved that would make it impossible," said Mr Robinson.

"I think when you start going for that degree of merging you are moving along an agenda that is very much a united Ireland agenda and I don't think unionists will buy into that. They will go for co-operation and collaboration but they will not go for merging and unity."

The DUP deputy leader said he could understand where Dr Gillespie was "coming from on this kind of issue, but there are major political and practical difficulties".

"You are dealing with two separate organisations who have different financial packages, different forms of answerability, different taxation, so there are all sorts of difficulties."

Mr Robinson said he thought there was scope for improvement in the collaboration between the IDA and Invest NI, and greater co-operation was "the way to go".