Scots-born businessman King issued a lengthy statement on Wednesday, hitting out at the Gers hierarchy and outlining his position amid speculation that he could plough more money into his boyhood heroes if a fresh share issue is launched to raise funds .
King urged fans to withold season ticket cash until they have assurances and answers from the under-fire board and Johnstone insists showdown talks need to be held urgently.
He told SportTimes: "I don't know how Dave King knows how the club is running just now.
"He is 6000 miles away in South Africa so how does he know what is going on at the club?
"I don't know how Dave would know unless he has spoken to them but we are getting mixed messages regarding what has been said. It is a situation Rangers can do without just now.
"In a few weeks' time, the fans will get letters through their door asking for season ticket money again.
"Now, you might get a fair percentage who will say, 'maybe Dave King is right' and he has put this idea into their heads.
"It all has to be settled and the way for it to happen is for Dave to come here or the chief executive to fly over to South Africa and see what is on his mind.
"The two of them have to meet. It has to be sorted quickly.
"Dave has money to put into the club, he has said that for a long time. Rangers need money. So there has to be a compromise.
"Go and speak to him and let's see if we can get a solution. You are always better doing business face-to-face and that is what Graham has to do."
King's statement was met with widespread acclaim from the Light Blue legions, many of whom are eager to see the multi-millionnaire return to the club.
But Johnstone is wary about his proposal and said: "The big problem Rangers have is that they need the season ticket money.
"If they don't get it then they are in big trouble, it is as simple as that.
"The fans have bailed the club out in the last two years by buying their season tickets and if, all of a sudden, that money isn't there and they are not going to do that then Rangers could be in real trouble."
King's radical plans were yesterday given a significant seal of approval by the Light Blue legions as tensions between the terraces and boardroom get set to rise once again.
The Rangers Union of Fans issued a vote of no confidence in the current Gers hierarchy as they backed King for a sensational Ibrox return.
Craig Houston of the Sons of Struth said: "The fans see him as the knight coming over the hill to help.
"A lot of fans, the feedback we're getting is that it sat nicely with their thoughts and views.
"It was a good statement and very hard-hitting; there's not a lot you can disagree with.
"There's been a lot of cry-outs for Dave King to get involved and speak out."