The vast Trans-Pacific Partnership, one of the biggest trade deals in history, was signed in New Zealand Thursday by all 12 member nations amid loud protests.

While New Zealand Prime Minister John Key and US Trade Representative Mike Froman led the ceremonial signing at Auckland's Sky City Convention Centre, protestors blocked roads outside.

The ambitious pact aims to break down trade and investment barriers between countries comprising about 40 percent of the global economy. 

However, protesters argue it will cost jobs and impact on sovereignty.