Given New York-based Insight Venture Partners' offer of US$4.90 ($7.39) a share, that stake would be worth about $26 million.
The deal, endorsed by the company's board, still requires shareholder approval.
"We were the sole provider of the pre-IPO funding, we funded the company into listing. We've been in there from [the listing price of] $1 all the way down to 7c at one stage and then all the way back up to $8.20 and now US$4.90, which is $7.40 or thereabouts," Huljich said.
Huljich is a former director of Diligent, which develops software used by board directors to access documents.
The Huljich family is valued at $165 million on the National Business Review's rich list.