Toshiba Corp's US nuclear unit could file for Chapter 11 protection from creditors as early as Tuesday, according to a source with direct knowledge of the matter, hoping to ring fence losses ahead of the end of its financial year. But whether the complex bankruptcy filing, which threatens to involve both the Japanese and US governments, can be achieved this week, remains to be seen. Separate sources with knowledge of the matter said last Friday Toshiba had informed its main banks that it was planning a March 31 filing for Westinghouse - the centre of its multibillion dollar crisis. "A March 28 filing is one proposal. The thinking is that it would great if we could pull that off but whether it goes that well or not, is another issue," the source with direct knowledge said. Sources declined to be identified as they were not authorised to speak publicly about the matter. Toshiba reiterated a previous statement that it was premature to comment on a potential bankruptcy. You may also like to watch: [jwplayer ocDzQJRZ] Westinghouse has been plagued by huge cost overruns and the financial maelstrom has already caused Toshiba to put up its prized memory chip unit for sale, consider a sale of a majority stake in the U.S. nuclear unit and miss deadlines to file earnings that have put it at risk of a delisting. At Thursday's shareholder meeting, Toshiba will seek approval for the sale of the chip unit. While a Chapter 11 filing for Westinghouse would be done by the U.S. unit's board and would not require approval by Toshiba's shareholders, a filing on the same day or directly before or after will increase the chances of contentious shareholder gathering. For that reason, Toshiba's main banks would prefer the Chapter 11 filing not come before the shareholder meeting, a financial source with knowledge of the matter said. A Chapter 11 filing for Westinghouse is set to increase charges related to the unit to 1 trillion yen ($9 billion) from a publicly flagged 712.5 billion yen estimate, sources have said. While that would be a much bigger-than-expected hit in the short-term, the TVs-to-construction conglomerate wants to prioritise limiting the risk of future losses at two U.S. nuclear projects in Georgia and South Carolina. The power plants Westinghouse is building are called the Virgil C. Summer Nuclear Generating Station in Fairfield County, South Carolina and the Vogtle Electric Generating Plant in Burke County, Georgia. Scana Corp and Santee Cooper own the plants in South Carolina, and Georgia Power leads a consortium that commissioned the Georgia plants. In any Westinghouse bankruptcy, the utility companies would be among the largest creditors of the developer, owed the work that has yet to be completed and potential penalties, sources have said. The Nikkei business daily reported on Monday that Toshiba has asked South Korea's Korea Electric Power Corp (KEPCO) to sponsor its Westinghouse bankruptcy reorganization. A Seoul-based KEPCO spokesman said that no request had been made.