The Maritime Union has sent a letter to Ports of Auckland accusing it of leaking confidential employee records, as the bitter waterfront dispute continues.
The union alleges the port company disclosed the leave details of wharf worker Cecil Walker to a blog site, after he spoke out publicly against the port company's collective agreement offer.
Mr Walker needed time off work in 2007 and 2008 because his wife was terminally ill.
On Tuesday, a breakdown of how many days he did not attend work due to his wife's illness was published on a blog site, along with other personal details.
Blogger Cameron Slater says he published the details, following an interview with Mr Walker on Radio New Zealand's Morning Report programme, because only half the story is being told in the industrial dispute.
Maritime Union Auckland secretary Russell Mayn says only the port company could have leaked the information, which should not have been published.
"This is not industrial matters, it's nothing to do with the strike. This was a tragic set of circumstances in his family that's now been bandied about on a website."
Mr Mayn says a letter has been sent to the port in the first stage of a Privacy Act complaint.
Mr Walker told Morning Report on Wednesday he feels violated and angry at the publication of the information.
He said that when speaking publicly earlier in the week he did not "have a go" at the company, but was talking about contracting and hours of work.
Ports of Auckland says it will investigate, but is not commenting further.
Listen to Cecil Walker
CTU seeks compensation
Council of Trade Unions president Helen Kelly says there is no doubt in her mind the Ports of Auckland leaked the confidential information.
Ms Kelly says the details of Mr Walker's leave are too specific to have come from anywhere else but the company.
She told Morning Report the company's action were vindictive and the union is seeking compensation for the port worker.