DUP MP Sammy Wilson has said resignations from the party are "not peripheral" - contradicting comments made by new leader Edwin Poots.
The East Antrim representative said there was no point denying there have been "rifts and splits and anger" as a result of the DUP leadership change.
But he rejected claims of a "purge" of disaffected party members who did not back Mr Poots for the leadership.
Mr Wilson said efforts are needed to mend divisions over the ousting of Arlene Foster as party leader and the subsequent narrow election victory of her successor.
Several party members including two councillors have resigned due to the split.
Mr Poots on Monday described the resignations as "peripheral" but said he would "continue to reach out to people", adding he did not wish to lose anyone from the party.
Speaking on the BBC's The View, Mr Wilson there was "an awful lot of internal party work to be done to ensure that everybody joins together".
He added: "Let me make it clear that anybody who leaves, and especially people who have given long years of service to the party and to Northern Ireland, if they leave, it is not peripheral."
Mr Wilson said it was "important we hold on to people" and he believed Mr Poots was also committed to retaining any disaffected members.
The MP also dismissed comments from defeated leadership candidate Sir Jeffrey Donaldson, who claimed there had been a "purge" of party members in South Down.
"You don't go about purging people especially when you've had a leadership election where it's been fairly evenly split," Mr Wilson said.
"Why would you want to purge half the party that didn't vote for the leader.
"That would be just nonsensical. It's not what Edwin's about, it's not what Edwin's supporters are about and it's not what we're about."
He described the DUP as a "family", adding: "Sometimes when families fall out it can be even worse than just when friends fall out, but the important thing is that we get back to understanding bigger issues to be dealt with."
Mrs Foster is due to step down as Stormont First Minister next week.
Lagan Valley MLA Paul Givan has been announced as the DUP's nominee for First Minister to replace Mrs Foster as part of Mr Poots' new frontbench team.
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