The future of the union depends on a strong and united Democratic Unionist Party, its leader Ian Paisley has said.
Ian Paisley said the DUP had "faced down republicans"
He was speaking after a meeting of disaffected unionists which discussed the formation of a new party opposed to the DUP sharing power with Sinn Fein.
The independent MEP Jim Allister, who quit the DUP over its devolution move, addressed the meeting.
First Minister Mr Paisley said their "so-called political platform" had been rejected by the electorate.
He added: "They have nothing to offer in terms of prosperity or stability for the province.
"Indeed many are more interested in attacking and undermining unionism than developing and strengthening the union in the longer term.
"The Democratic Unionist Party has succeeded in strengthening the union by facing down republicans and insisting upon our demands."
Jim Allister addressed a meeting of disaffected unionists
About 100 concerned unionists met in County Tyrone on Wednesday evening to discuss their next move.
Mr Allister said it was clear that unease and opposition to the DUP and Sinn Fein in government was growing.
"The task now is to channel this opposition - it is a work in progress," he added.
Mr Allister, who declined to take questions but read a statement to the media, said it was one of a series of meetings.
Among those attending were Robin Sterling and Leslie Cubitt, two former DUP councillors who quit the party this year.
Mr Allister, who previously left the party in the 1980s after a disagreement, was opposed to the DUP executive's resolution committing to power-sharing.
He said: "The lure of office has clouded the party's judgment".
Others who attended the meeting told the BBC that most unionists in attendance supported the formation of a new unionist party.
The former East Londonderry MP, Ulster Unionist William Ross, said for some time unionists who opposed the DUP sharing power with Sinn Fein had been stunned into inaction.
"It has taken some time for people to get back on their feet, but they're getting back on their feet," Mr Ross said.
However, the current MP for East Londonderry, Gregory Campbell, said there was little support for any new unionist grouping.
"I detect amongst the wider unionist community no appetite whatever for yet another unionist grouping," Mr Campbell said.