Picket lines have been drawn at major Australian ports with workers refusing to unload ships as a rowdy union protest builds in support of workers sacked via late- night text and email.

Maritime Union Australia members and those supporting the workers have maintained a picket line at Sydney and Brisbane ports over the weekend, after Hutchison Ports Australia notified 97 of its 224 workers that their jobs were terminated on Thursday.

Local media reported the striking workers will refuse to unload the first boats to arrive into Sydney and Brisbane on Monday, the first since the protests began.

Hutchison Ports has blamed the job cuts on substantial financial losses, saying the company is moving to downsize operations.

The Maritime Union of Australia has refuted the claim, saying the moves are part of the company's push to increase automation of port services.

Maritime Union of Australia national secretary Paddy Crumlin called on Hutchison Ports to release all labor data and modeling to support its claim.

"Sacking workers by text and email effective immediately is not the Australian way," Crumlin said, noting a precedent has now been set for terminating staff.

A hearing has been scheduled at Australia's Fair Work Commission in Sydney to resolve the matter on Monday afternoon.