The head of South Korea's top financial authority on Thursday lashed out at Taeyoung Engineering & Construction's self-rescue efforts, saying they fell far short of expectations and urging a new plan within the week.

Financial Supervisory Service chief Lee Bok-hyun made the comments during his New Year's press conference at the FSS headquarters in Seoul earlier in the day, just a day after the ailing construction firm announced a set of self-rescue plans to overcome a liquidity crunch stemming from real estate project financing loans.

"The authorities are concerned as Taeyoung has failed to carry out the least of its pledges to provide support to minimize the loss suffered by the subcontractors, purchasers and creditors," Lee said, explicitly criticizing the insufficiency of the company's efforts.

"Taeyoung enjoyed over 1 trillion won ($764 million) in profit by taking on several projects at once, which contributed largely to expanding the wealth of the ownership family. But now, with the real estate market downturn, it is the partners, customers and creditors who take on the burden, not the major shareholders," he added.

Taeyoung Group Founder Yoon Se-young on Wednesday held a meeting with some 400 creditors and revealed self-rescue schemes to support the debt-ridden builder. The plan included utilization of the proceeds from selling off its subsidiary Taeyoung Industry, sales of other affiliates including Ecorbit and BlueOne and putting up collateral such as its 62 percent stake in grain handling and storage company Pyeongtaek Silo.

However, the creditors doubted that Taeyoung E&C would be able to execute such plans. Speaking with journalists following the creditors session, Kang Seog-hoon, chair of the builder's main lender Korea Development Bank, expressed disappointment at its failure to keep pledges pertaining to debt relief. KDB claimed Taeyoung E&C only provided 40 billion won from the originally promised 154.9 billion won gained from selling Taeyoung Industry.

Taeyoung E&C applied for a debt workout program last week. It requires 75 percent approval from creditors to initiate the workout process, and the final decision for the workout initiation will be determined at the creditors' meeting slated for Jan. 11.

The FSS governor called for a renewed self-rescue plan from the builder by the weekend.

“We can’t take a plan like this to the meeting next Thursday and ask them to agree to it," Lee said. "The KDB also has to persuade other creditors and there won’t be enough time left if this matter (of insufficient efforts) continues into next week."

Lee asked the government to even consider calling off the workout process if the creditors are not persuaded by the firm's self-rescue efforts.

“The authorities are doing our best to stabilize the market, taking under consideration various possibilities," he said.

"We promise to take sufficient measures preemptively to make sure that the situation does not spread to the overall construction industry."