"I urge those who know the truth to leak your information to the media. Please help us."
The call comes after a series of blunders and the extraordinary revelation that the GCSB spy agency had illegally snooped on Dotcom.
Mr Dotcom said he was concerned about meetings between Mr Key and ministers in his cabinet with US government officials involved in copyright discussions and a prominent Hollywood lobbyist.
"The recent memory lapses and attempts of obfuscation are disturbing. I think it would benefit all New Zealanders to have an independent inquiry for full transparency."
Mr Dotcom said Megaupload - which pulled in 4 per cent of internet traffic at one stage - was "legitimate ... just like Youtube or Dropbox".
"The case against us is without merit and we will prevail. But in the meantime our lives and businesses are destroyed."
- David Fisher of the New Zealand Herald