Derrick Walker has threatened to take legal action against former team co-owner Craig Gore.
Walker and Gore's three-year-long Team Australia partnership dissolved earlier this month, with Gore taking his funding and driver Will Power to KV Racing instead.
As a consequence of Gore's departure, Walker Racing had to abandon their IRL IndyCar plans, despite having been among the first to commit to the merged series.
In addition to his anger at Gore for pulling out at short notice, Walker also claims the Australian owes his team significant sponsorship from 2007.
"I was extremely disappointed by Craig Gore's announcement to take Team Australia, our driver, and sponsors to KV Racing," Walker said in a statement.
"Contrary to Gore's recent statements, I developed the concept of Team Australia in 2005. Over a three-year period, Team Australia had great success in using motor sports as a marketing tool for Australian companies, including Gore's winery, Aussie Vineyards.
"Despite the success of the team, Gore defaulted on his financial obligations to Team Australia throughout the 2007 season. Walker Racing was forced to loan the team substantial funds in order to continue competing in the Champ Car World Series.
"Walker Racing is still owed in excess of $1,500,000 by Gore and his related entities. I relied upon Gore's repeated assurances that he would fulfill his commitments to the Team Australia program and to me.
"Until Gore's recent announcement to take Team Australia to KV Racing, I was led to believe that we would be moving forward together as a team in 2008.
"I believe that Gore's actions are a serious default of his contractual commitments and fiduciary obligations as a business partner. I have given Gore ample opportunities to resolve these disputes informally. Unfortunately, it appears I will have no choice but to take legal action."
Gore joined forces with Walker to create the Team Australia project at the start of the 2005 season, with Power taking their first victories last year and challenging for the final Champ Car title.
Although Walker has not completely given up on joining the IndyCar Series during 2008, his team are currently focusing on the Atlantic series and investigating opportunities in A1GP.
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