Recruitment firm Hudson says a technical glitch was responsible for an advertisement seeking Australian workers for Ports of Auckland.
More than 300 union members are on a three-week-long strike after months of stoppages, failed negotiations and stand-offs over proposed changes to their conditions.
Maritime Union president Garry Parsloe said he was astounded to find Ports of Auckland had begun advertising dockworkers' jobs in Australia.
The port company said it thought the ads would only appear in New Zealand.
Hudson has now confirmed the listing was posted in Australia by mistake and has now been removed.
Meanwhile, the Maritime Union says its Australian counterpart has pledged total support to workers caught up in the dispute.
Mr Parsloe says the Australian union has promised a substantial amount of financial support and carried a resolution of support to provide anything else the workers may need.
He says the union has also recieved support from American, Canadian and Dutch counterparts.