"The biggest creditors by miles, by a significant margin, are them. They've ploughed in hundreds of thousands of dollars ... probably near a million unfortunately."
Walker estimated other external creditors were owed about $220,000.
"Looking at what I'm going to get for the assets, there's not going to be a lot to spread around the external trade creditors," he said.
"There'll be something. If they [external creditors] get 10c in the dollar I'll be surprised."
Walker said two parties unrelated to the business were lined up to buy the firm's intellectual property and its stock.
Zumwohl was created by Ulf Fuhrer after he struggled to find German-style schnapps in New Zealand.
One of his business partners was Anthony Green, who was the original producer of 42Below Vodka.
According to the Companies Office, Fuhrer owns 12.3 per cent of Aotearoa Distillers while Green owns 8.4 per cent.
Fuhrer did not return a call for comment yesterday.
This story has been amended from an earlier version that said the Customs Service was the petitioning creditor.