The leaky building class action against cladding manufacturer James Hardie is being heard in the High Court at Auckland this week.

The action claims James Hardie was negligent in its design, manufacture and supply of the Harditex and Titan Board cladding systems and involves more than 1000 owners of 365 buildings, including 29 large body corporates.

The James Hardie group of companies denies the claims.

Adina Thorn of Adina Thorn Lawyers said the plaintiffs alleged they had suffered financial losses and significant health issues arising from the use of non-performing cladding materials marketed as "Harditex", "Monotek" and "Titan Board".


Last month the High Court ruled that 15 new plaintiffs could join the action, a decision that had been contested by James Hardie.

The hearing at the High Court in Auckland is expected to run for up to three days and will cover:
Summary Judgment Applications - Two of the seven James Hardie defendant companies have applied for early judgment in their favour (to be removed from the claim). The plaintiffs have opposed these two applications.

Protest to Jurisdiction - The parent company of the James Hardie group, James Hardie Industries, has opposed the claim being heard in New Zealand. The plaintiffs are opposing the application.

Particulars - The defendants are seeking further details of the plaintiffs' claims against them.

James Hardie was founded in Melbourne in 1888 by Scottish immigrant James Hardie. It is now listed on the Australian and New York stock exchanges and has its headquarters in Dublin.

In the 2016 financial year it generated net sales of US$1.73 billion ($2.44b).