The fate of NSW Labor boss Kaila Murnain could be sealed on Wednesday when she gives evidence to the corruption watchdog, with senior party sources warning her career was "all but over".

Sensational evidence emerged on Tuesday that Ms Murnain allegedly saw an Aldi shopping bag full of cash after it was dropped at the party’s headquarters by Chinese billionaire Huang Xiangmo.

Kenrick Cheah and NSW Labor general secretary Kaila Murnain in a photo from Cheah's Facebook page in August 2013. Credit:Facebook

Ms Murnain will give evidence to the Independent Commission Against Corruption (ICAC) after already telling ICAC that she had learnt that Mr Huang, a banned donor, was the "true source of the funds".

The evidence has rattled Labor insiders and MPs, who warn that her appearance before ICAC could be the "trigger" that ends Ms Murnain's reign as the first female general secretary of the NSW party.