CKI, who first launched the bid for APA in June this year, is offering a price of $11 per share for the infrastructure business in a move that would cost around $13 billion.
The bid also permits APA securityholders to receive a dividend of $0.24.
APA Chairman Michael Fraser said CKI had made a good offer.
“The offer made by the CKI Consortium is compelling,” he said.
“It is an all cash offer, representing a premium of over 30 per cent to APA’s recent trading prices and gives a certainty of value to securityholders.”
CKI now needs to receive regulatory approval for the takeover from the ACCC, with the competition watchdog expected to deliver a response in September.
With a network of natural gas pipelines spanning around 15,000 km, APA owns and operates an extensive infrastructure portfolio value at more than $20 billion.