Mr Scargill, who led the union through a bitter year-long strike over pit closures in the 1980s, is among several people who have received letters apparently saying they no longer qualify for membership.
The union's former president could not be contacted for comment last night, but he has told friends he intends to fight the move.
He retained an honorary position within the NUM after standing down as a full-time official and has been engaged in work for the union.
Another official, Ken Capstick, who has worked for the union for 30 years and currently edits its Miner magazine, has also been told he is being expelled.
Mr Capstick said: "We have been told that the reason we are being expelled is that we don't qualify under the union's rules.
"A number of us have been raising claims of financial irregularity in the union and I believe we are now being subjected to a witchhunt because of this. We will definitely challenge this decision, which has been made on extremely spurious grounds."
The NUM and Mr Scargill proved to be a thorn in the side of the then Prime Minister Margaret Thatcher during the bitter miners strike of 1984-85.
NUM national secretary Chris Kitchen later said: "Arthur saying that he's been expelled is not correct. It's whether he should qualify under the national rule book as a full financial member, not whether he should be a member.
"There are other categories of membership that he does qualify under – he'll be a member of the NUM, either a life member or a retired member, or possibly an honorary member given he's the honorary president of the NUM.
"I should imagine that Arthur will be against it but unfortunately we have to abide by the rule book and he has been party to drawing that rule book up."
Steve Kemp, who was general secretary of the NUM between 2002 and 2007, received a letter yesterday telling him that he could no longer continue to be a full member of the union.
He could become a retired member or a life member, which Mr Kemp said involved "heavily watered down" rights.
Mr Kemp has been in the NUM for 31 years and stayed as a full member after leaving to work for the GMB.
He said last night that one of the reasons he stayed in the union was out of pride for the NUM.
"It looks as though the Yorkshire region has decided to look at the membership and get rid of a number of members which is astonishing especially at a time when unions are facing cuts and are losing members.
"It is all very, very sad and disappointing that a great union has decided to take this course of action, but I will fight this decision," he said.
Mr Kemp claimed that those who had received letters from the union saying they could no longer remain as full members were told they could not appeal against the decision.
He added that it could be argued that the national union was expelling those who had received letters.