New proposals mean Charity Commission for Northern Ireland would not be able to start registering charities until September.
Education and poverty charities could be granted an exemption to the public benefit test in Northern Ireland.
The Northern Ireland executive, a body of 13 ministers, last month asked the Department for Social Development, which is responsible for the implementation of the Charities Act 2008, to draft an amendment to the act that would reintroduce a presumption of public benefit for charities that aim to advance religion.
It has since told the department that this amendment should also apply to charities whose purpose is to advance education or relieve poverty.
The move means the Charity Commission for Northern Ireland is unlikely to be able to start registering charities until September at the earliest because the amendment will not be passed before the Northern Ireland Assembly is dissolved in advance of elections for the executive in May.
The amendment would also say that charities in Northern Ireland should have their public benefit tested on the model used in England and Wales, rather than that used in Scotland.
Lawyers had pointed out that Northern Ireland's Charities Act 2008 created a public benefit test that was open to challenge because it was a hybrid of English and Scottish law.
Roy McGivern, head of charity policy at the Department for Social Development, told Third Sector his department would draft a legislative amendment that contained the provisions for using the English public benefit model and for reinstating the presumption of public benefit for charities whose objects were to advance religion or education, or to relieve poverty.
It would be up to the new minister after the election to introduce this amendment to the assembly, and the new minister would be able to change its contents, he said.
"It is the department's view that there should not be a presumption of public benefit for any charities, and this is what the 2008 act says," he said. "However, the executive has taken a different view. Our worry is that this takes us out of step with the legislation in the rest of the UK."
A spokesman for the Charity Commission for Northern Ireland said: "Obviously, we would prefer to begin registering charities as soon as possible."
He said he was unable to comment on the provisions to reintroduce a presumption of public benefit for certain charities.
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