Newcastle want the Scottish quartet Doddie Weir, Gary Armstrong, Peter Walton and George Graham, plus Ireland's Nick Popplewell and Ross Nesdale, for a Second Division match against Rotherham on Saturday.
After initially agreeing to a postponement, Rotherham are refusing to switch the game, which clashes with Scotland's Test against Australia, Scotland A's international with South Africa A and an Irish squad session.
"As far as I am aware, the International Board ruling says national teams have first call on players," Hastie said. "England brought out a ruling that three England players had to be involved before a club could get dispensation to reschedule a league match. The regulations do not mention anything about Scottish players."
Rob Andrew, the Newcastle director of rugby, is reluctant to withdraw his players from international squads, but because of a rule change the club are powerless to insist on a postponement.
"We have asked the RFU and Epruc to try to find a workable solution, and that must be done quickly," the club said in a statement.Reuse content