Shareholders embroiled in a class action lawsuit against Aegean Marine Petroleum Network's former officers and auditors are moving to block parts of the bankrupt bunkerer's reorganisation plan.

In court papers filed Tuesday, lead plaintiff Utah Retirement Systems alleges part of the plan makes their securities fraud lawsuit against founder Dimitris Melissanidis worthless by prioritising future litigation by the New York-listed bunker supplier's unsecured creditors on the same issues.

"[This] is nothing more than a brazen attempt to strip [Utah Retirement Systems and its co-plaintiffs] of their direct claims ... in the hope of bolstering other parties' recoveries from the same defendants," the court papers read.

The US pension fund filed two lawsuits over the summer, alleging Melissanidis, Deloitte, Pricewaterhousecoopers and other directors engaged in insider trading, related party transactions and fraud. The lawsuits, which came after the company disclosed it had to write off $200m in accounts receivable, were combined in October and an amended complaint was filed 1 February.

Meanwhile, Aegean declared bankruptcy that November. The move came after it announced the $200m in accounts receivable was part of a larger scheme that saw money funneled to companies controlled by an "unnamed former affiliate" later identified as Melissanidis.

In December, Aegean and its unsecured creditors came to an agreement that saw them pay $40m and the proceeds from litigation against Melissanidis in exchange for their support in reorganizing the company. The unsecured creditors had previously argued the litigation claims were arguably the most valuable part of the business and should be assigned to them.

Utah Retirement Systems and their co-plaintiffs argued Tuesday that part of the plan subordinates their claims to the unsecured creditors'.

The plan, they say, includes "sweeping and virtually incomprehensible" third-party releases that, in order to oppose, parties must opt-out of.

If passed, the class action plaintiffs would allegedly only see money from the litigation claims if proceeds surpass $272m.

The US trustee has also called out the issue of the third party releases arguing in an objection, also filed Tuesday, that it does not provide "adequate information" on the releases and the legal basis that the plan will be approved including them.

Aegean did not immediately return a request for comment.

Speaking with TradeWinds last month, Aegean director Tyler Baron — not named as a defendant in the Utah Retirement Systems lawsuit as he was not on the board until mid-last year — said he expects the company to emerge from bankruptcy in March.

He said the backing from Swiss commodities trader Mercuria Energy group gives Aegean Marine the backing necessary to truly fully leverage its worldwide refueling network.