Self-styled whistleblower website WikiLeaks is offering $100,000 for copies of the Trans-Pacific Partnership draft, which some see as a central plank of President Barack Obama's diplomatic pivot to Asia.

WikiLeaks has published leaked chapters of the TPP negotiating text before, but on Tuesday began a drive to crowdsource money for the reward, just as U.S. unions launched a new push to make the text public.

"The transparency clock has run out on the TPP. No more secrecy. No more excuses. Let's open the TPP once and for all," WikiLeaks founder Julian Assange said in a statement.