It is rare that a firm seeks to extend a payment again within a short period, highlighting the stressed liquidity of the country's No.3 property developer by sales.
The 400 million yuan ($59.57 million) payment due June 30 is first of the six instalments of a 4 billion yuan puttable bond that Sunac had extended from April 1 by 18 months.
Financial news and research provider REDD first reported about the talks between Sunac and major bondholders.
Sources said Sunac was still raising money for the payment, and it planned to pay part of it on the due date and extend the rest. Details are still being finalised and are expected to be announced next week, still subject to bondholders' approval.
Sunac declined to comment.
The next instalment worth 600 million yuan is scheduled to be paid on Sept. 30.
Sunac is trying to ease its cash crunch by extending debt obligations and disposing of assets, after its sales were hit by COVID-19 this year and it was unable to secure new financing.
A source told Reuters Sunac was working on a restructuring of its offshore debt, aiming to finalize it in the next two to three months. It was also talking to state-owned entities about strategic investments in the firm.
Last month, Sunac missed the deadline for coupon payments on a $742 million offshore bond and said it did not expect to make payments coming due on other bonds, adding to a wave of defaults in China's debt-laden property sector.
($1 = 6.7152 Chinese yuan renminbi)
(Reporting by Clare Jim in Hong Kong, Steven Bian in Shanghai and Shuyan Wang in Beijing; Editing by Tomasz Janowski)