The Prime Minister has been urged to "reach out" to the DUP by one of his own MPs amid claims senior Conservatives are secretly preparing the way for a power-sharing deal after the next General Election.
With less than a year until the election, opinion polls still suggest the Tories and Labour will both struggle to claim an outright victory.
Privately, Conservative MPs believe they can emerge as the largest party – even if they fall short of the 326 seats needed for a majority.
With support for the Liberal Democrats plummeting, and some Tories opposed to another coalition with Nick Clegg, the DUP could hold a powerful hand come next May.
Now a Conservative MP has made a public plea to David Cameron to explore a deal with the party.
Mel Stride, who is an aide to the Prime Minister's senior parliamentary adviser, said his party should "reach out now" to the DUP.
He pointed out that when a similar deal was mooted before the 2010 election, the DUP was said to be demanding a commitment to cancel £200m of cuts to Northern Ireland's public sector.
"More sensible terms should follow from a better relationship with some issues scoped out in advance," he said in the Daily Mail.
"Coalition government has taught us the importance of developing and nurturing connections with other political parties."
Mr Stride pointed out that the DUP was the only other party that had backed a Conservative commitment to give voters a say on Britain's membership of the EU. The same article quoted what it described as a "well-placed source" who said: "The DUP is definitely being wooed.
"Of course people are thinking about these things."
Last month, Mr Cameron hosted a lavish Downing Street reception for DUP MPs.
One Tory cabinet minister conceded there was "a lot of cosying up" to the DUP behind the scenes and there was "much talk of them helping keep a minority Tory administration in business".
However, DUP MPs have branded the remarks "mere speculation" and said they were unaware of any formal approach having taken place.
Lagan Valley MP Jeffrey Donaldson told the Belfast Telegraph: "All of this is speculation and I'm not aware of anything formal having been discussed between the parties.
"The DUP is very clear that our role is to act in the best interests of Northern Ireland within the context of the United Kingdom and we will view any future government of the UK in that light."
The DUP is currently the fourth largest party in Parliament with eight seats.