The claim was brought under part 271 of the Companies Act, a section which is rarely invoked and unique to New Zealand.
It provides an exception to the principle that shareholders are not exposed to the obligations of a company beyond the extent of their liability for payment of share capital.
In an interim decision, Justice Alan Mackenzie said Stube's directors did not make a distinction between the interests of Steel & Tube and those of the subsidiary.
"They saw only one set of interests involved, the overall interests of the group ... they did not hold formal board meetings for Stube. Nor did they sit down together to discuss matters with a conscious appreciation that they were doing so with their Stube directors' hats on."
The judge also said the evidence supported the proposition that Stube was treated as a division of Steel & Tube Holdings, for financial purposes.
Justice Mackenzie found it was just and equitable that Steel & Tube Holdings should pay the whole of Lewis' claim but what that amounted to would be determined after another hearing.
Steel& Tube Holdings spokeswoman this morning confirmed the company was appealing the decision.
Law firm Chapman Tripp, in a commentary released last month, said directors must be careful to ensure the interests of a parent and subsidiary are kept distinct.
This included keeping separate records and resolutions and ensuring outgoings are being invoiced to and paid by the appropriate company.
There also needed to be formal legal arrangements when providing financial support from parent to a subsidiary.
"Failure to take these steps will create a risk that a court will hold the parent liable for the debts of its wholly owned subsidiary," said the law firm, which was not involved in the case.
