"(CK Hutchison) remains in discussions with members of the consortium with a view to inviting (a) major strategic investor from (China) to join as a significant member of the consortium," the group said in a stock exchange filing.

The firm added that changes to the consortium's membership and deal structure will be needed for the deal "to be capable of being approved by all relevant authorities".

CK Hutchison announced in March it was offloading its global ports business outside China -- including operations in the vital Central American waterway -- to a group led by asset manager BlackRock for $19 billion in cash.

The sale was seen as a political victory for US President Donald Trump, who had vowed to "take back" the Panama Canal from alleged Chinese control, drawing Beijing's ire.

China's market regulator said in March it was reviewing the deal.

CK Hutchison said Monday that the "period for exclusive negotiations" mentioned in the March announcement had expired, but that discussions will continue.

It did not name the major Chinese investor.

China's biggest shipping company Cosco was set to join the consortium and was requesting veto rights or equivalent powers, Bloomberg News reported.

CK Hutchison said it "intends to allow such time as is required for such discussions to achieve" a workable arrangement.

It said it had stated on several occasions that it "will not proceed with any transaction that does not have the approval of all relevant authorities".