Secretary of State Theresa Villiers has refused to be drawn into the debate about the potential impact on Northern Ireland of Britain's exit from the European Union.
But her under secretary Ben Wallace has fuelled speculation over differences of opinion within the NIO team by voicing pro-EU sentiments.
Mrs Villiers is reported to be considering campaigning against the UK's continued membership of the EU in a referendum due this year – a move that would cause serious concern among the north's pro-European parties.
However, NIO minister Ben Wallace told MPs during Northern Ireland questions at Westminster yesterday that he believes a reformed EU is "where the United Kingdom wants to be".
DUP MP Sammy Wilson tried to push Ms Villiers to back a British exit – referred to as 'Brexit' – as he cited the positives of leaving.
"While the devolution of corporation tax will be important in growing the Northern Ireland economy, would you also agree that a vote to leave the EU would help the Northern Ireland economy insofar as it'd release £18 billion every year for expenditure on public services, would enable us to enter trade agreements with growing parts of the world and would release us from the stifling bureaucracy of Europe?" the East Antrim MP said.
But Ms Villiers declined to voice an opinion either way.
"We promised a referendum in our manifesto, that's what we're going to deliver," she said
SDLP MP Margaret Ritchie had earlier asked Mr Wallace whether he would encourage Ms Villiers to argue for a yes vote.
Mr Wallace replied: "I think there's a temptation in front of me. I think what I'd say is certainly up to date, membership of the European Union has been good for Northern Ireland."
Shadow Northern Ireland Secretary Vernon Coaker also warned there is "very real concern" in the north about the impact of leaving the EU on trade and investment.
