A single unionist party is needed to maintain the union, the head of the Orange Order has said.
Grand Master Robert Saulters said there was "too much division".
The UUP is reviewing its operations after its failure to gain a single MP, the TUV failed to significantly dent the DUP's vote, and DUP leader Peter Robinson lost his seat to the Alliance.
"We will continue to dilute the union if we fight and bicker among ourselves," said Mr Saulters.
He was speaking in north Antrim at the reopening of Lavin Orange Hall, which has been rebuilt after it was destroyed by an arson attack in July 2006.
'One big unionist party'
Mr Saulters said the Orange Order had members "who represent all the many shades of unionism".
"There is a huge groundswell of opinion that there must be a drive towards unionist unity or at the very least better joined-up thinking between unionists," he said.
"Personally, I believe there should be one big unionist party which represents all the views that I hear.
"It must be a party that is big enough and modern enough to allow people with conflicting opinions to work together for the common purpose of maintaining the union."
Last December, the Orange Order convened secret unity talks between the DUP and Ulster Unionists at its Belfast headquarters.
The two parties discussed the possibility of electoral pacts and forming a unionist bloc at Stormont, although the talks did not involve the Conservative Party, the UUP's election partners.
The talks did not result in a concrete merger, although the two parties fielded unionist unity candidate Rodney Connor in Fermanagh and South Tyrone in an attempt to unseat Sinn Fein's Michelle Gildernew.
Mrs Gildernew retained her parliamentary seat by a margin of four votes.