The New Zealand High Court has given permission for a leaky building class action to proceed against cladding maker James Hardie.

The action claims James Hardie was negligent in its design, manufacture and supply of the Harditex and Titanboard cladding systems.

The first Harditex claim was brought by Tracey Cridge and Mark Unwin, who claim their Wellington home suffered widespread internal water damage – estimated to cost more than $300,000 to fix.

Another Wellington couple, Katrina Fowler and Scott Woodhead, have also claimed over their 2000 duplex.

James Hardie denies the claims and has said it stands by the integrity and quality of its building products.

It would vigorously defend any allegations made against its products, it said when the class action was revealed last year.

Lawyer Dan Parker said 19 commercial owners had signed up for the Titanboard claim, and more than 60 for the Harditex claim. Last year Mr Parker said more than 500 people had contacted them about potential claims.

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 $US1.73 billion.