News agency TT reports that Rehn has the support of a number of party districts and 12 of 13 politicians in the region of Västra Götaland.
But a zero-tolerance policy against "extremists" and "racists" expressed by party leader Jimmie Åkesson could result in his expulsion. Rehn has previously said he regrets the time he spent as a member of a Swedish nazi party in the 1980s.
"If they expel me it would be very remarkable. I lead the party in Gothenburg and in the region. I am the lead author of the budget proposal here, and everyone who works with me knows I share the party's values," Rehn tells news agency TT.
Decisions on whether or not to expel Rehn and an unspecified number of other party members will be made at a meeting on Monday evening.