The former Royal spokesperson for Buckingham Palace, Dickie Arbiter, has told TVNZ1's Seven Sharp that the documentary Diana: In Her Own Words airing in the UK this weekend should come out, but not now.
The candid documentary, using videos filmed by her speech coach, comes ahead of the 20th anniversary of Princess Diana's death on August 31, 1997.
It also comes with lengthy legal battles, bitter accusations and high controversy, Seven Sharp reported.
Asked what the problem is with the tapes resurfacing, Mr Arbiter said it's a question of decency.
"It's respecting the individual's privacy. I don't think anyone really wants to hear about Diana and Charles' sex life," he said.
"I don't think anyone wants to hear the fact that, as Diana put it, the prince was all over her like a rash," he added.
"You know, these things are between two people, and they are private. There are those who suggest that, well, it is history, it should come out. Maybe it should. I agree with that. But not now."
It's about money at the end of the day. I'm not terribly sure it's all about entertainment"
Dickie Arbiter, former Buckingham Palace spokesman
In a preview clip from the documentary, Princess Diana, refers to her relationship with Prince Charles, saying: "We met 13 times before we got married. I was brought up in a sense that, you know, when got got engaged with someone, you loved them."
Britain's Channel Four, which is airing the documentary, paid for the footage.
"It's about money at the end of the day. I'm not terribly sure it's all about entertainment," Mr Arbiter said.
"They claim that it's in the public interest. Well who decides what is in the public interest? They're not judge and jury."
The former palace press officer said how much Channel Four paid for the footage is anybody's guess, "but I certainly don't think it was a paltry sum", adding "I think the voice coach, Peter Settelen, made a tidy sum out of it".
Mr Arbiter said Kensington Palace have made it known that neither princes William nor Harry are going to be reacting to the documentary, and that the princes have told their friends not to react to it.