INVEST NI has said it briefed First Minister Arlene Foster on the Republic's "poaching" of investment while on an American trade mission without Martin McGuinness.
It has been normal practice for the two joint heads of the Northern Ireland Executive to visit the US together, but in September Mrs Foster embarked on a four-day trade mission without the deputy First Minister.
At the time the Executive Office said there was nothing unusual about the pair travelling individually overseas, but it has now emerged important information about investment opportunities in the north may have been shared without the deputy first minister present.
The confirmation from Invest NI comes after the First Minister accused the Republic's government of talking down the north's economy and attempting to "poach our investors" at the DUP party conference on Saturday.
While the DUP did not respond to a request for information on any briefing between the First Minister and Invest NI, the latter confirmed discussions had taken place about a "specific approach" made by the Republic's Industrial Development Authority (IDA).
"The First Minister became aware of the specific approach adopted by the IDA during a recent visit to the US, with Invest NI, where she met with potential investors," Invest NI said.
The response from Invest NI has also shed light on the direct competition between the body and the IDA for investment, indirectly referenced during the First Minister's address.
"Invest Northern Ireland competes for inward investment with over 100 other development agencies, including IDA. It is clear from the already published Irish Government Contingency Framework that it planned to 'intensify [marketing] in key sectors...and identify the potential for new FDI arising from the UK leaving the EU'," they said.
Following Minister Foster's comments on Saturday the deputy first minister said he was "surprised" by the remarks made in relation to IDA representatives poaching Northern Ireland business.
Speaking on RTÉ’s This Week, Mr McGuinness said: "I was very surprised to hear Arlene say that at her party conference, given that earlier this week she and I met with a Chinese invest and we were accompanied by the Chief Executive of Invest NI, and this wasn't mentioned."
When contacted on Tuesday the IDA said it was "not in a position to make any further statements regarding this issue at this time".
The Department of Foreign Affairs also chose not comment on the latest development.
"It is normal for ministers to be briefed by Invest NI on overseas visits where there is the potential to attract investment," Sinn Fein said in a statement on Tuesday night.
"Martin McGuinness will travel to the United States next week and will receive specific briefings from Invest NI during the course of the visit.
"If individual ministers are travelling abroad it is obviously not possible to conduct joint briefings .
"However, any politically sensitive or significant briefing given to the First Minister would normally be shared with the deputy First Minister."
"If such a briefing was provided, we will be asking why this was not shared."
