HONG KONG, Jan 2 (Reuters) - Hong Kong pro-democracy tycoon Jimmy Lai pleaded not guilty on Tuesday to all charges levelled against him in a high-profile national security trial.

Lai faces two counts of conspiracy to collude with foreign forces - including calling for sanctions against Hong Kong and Chinese officials - under a China-imposed national security law which could see him jailed for life.

He is also charged with conspiracy to publish seditious publications under a colonial-era sedition law. (Reporting by Jessie Pang; Editing by Anne Marie Roantree and Editing by Sonali Paul)