
Sonthi spoke to Channel 9 on Monday morning from Kuala Lumpur where he is on an official visit.
He said he did not anticipate that voters in the Northeast would reject the charter or that residents in the North would just back it.
"I think many people have yet to gain an understanding of the charter provisions," he said.
He blamed anti-coup campaigners for spreading false information about the draft provisions.
He said he would instruct soldiers to reason with the public, many of whom have not read the charter draft.
Sonthi said enforcement of martial law in selected border provinces would continue for security reasons and had nothing to do with preparations for the election.
"The general election will proceed as has been planned and security measures will not impact on campaigning."
He reiterated that the poll should take place by year's end unless there were unforeseen circumstances.
He said he would not comment on his future before his retirement on September 30.
Air Force chief Air Chief Marshal Chalit Pukbhasuk said Sunday's referendum was a success because the "yes" vote topped those who voted "no" by almost 20 per cent.
With the charter paving the way for the general election, it was a good time for rival camps to stop protesting and allow the country to move forward, he said.
Meanwhile, rumours spread on Monday that the government might transfer provincial governors and local police chiefs who failed to ensure a "yes" vote in their areas on the charter.
But a security official, speaking on condition of anonymity, denied there would be any punishment of officials in areas where the charter was rejected.
"The annual rotations of soldiers, policemen and civilians will take place in September and has nothing to do with the referendum vote," he said.