An emotional Tim Paine has quit as Australia's Test captain less than three weeks out from the Ashes after a historic sexting investigation became public.
The veteran wicketkeeper, who has been facing a race against time to be fit for the first Test against England on December 8, was named in a News Corp report for sending explicit messages to a female co-worker.
The messages date back to 2017 before Paine was recalled to the Test team after a seven-year absence.
Paine fronted media in Hobart on Friday to announce he was resigning from the captaincy but stressed that he wanted to remain a member of the Test squad.
The 36-year-old read out a brief statement but did not answer questions.
"It's an incredibly difficult decision, but the right one for me, my family, and cricket," he said.
"As background on my decision, nearly four years ago, I was involved in a text exchange with a then-colleague.
"I'm deeply sorry for the hurt and pain that I have caused to my wife, my family, and to the other party.
"I'm sorry for any damage that this does to the reputation of our sport."
Paine was elevated to captaincy in March 2018 following the explosive fallout from the ball-tampering scandal in South Africa. Fast bowler Pat Cummins is Australia's current vice-captain and had been tipped to assume the role once Paine retired.
"Tim felt it was in the best interests of his family and Australian cricket to take this decision to step down as captain," CA chair Richard Freudenstein said.
"The board has accepted Tim's resignation and will now work through a process with the national selection panel of identifying and appointing a new captain.
In the statement, Freudenstein acknowledged an investigation cleared Tim of any breach of the code of conduct some years ago but CA respected his decision.
"CA does not condone this type of language or behavior," he said.
"Despite the mistake he made, Tim has been an exceptional leader since his appointment and the board thanks him for his distinguished service."
Cricket Tasmania released a statement claiming the allegations raised against Paine were only raised when the female employee was charged with theft. CT chairman Andrew Gaggin said no complaint was made until mid-2018 following the message exchanges in November 2017.
"As soon as Cricket Tasmania was made aware, it undertook an investigation that determined the interaction was consensual, private, occurred on the one occasion only, was between mature adults and was not repeated," Gaggin said.
Paine has played 35 Tests for Australia, taking 150 catches behind the stumps, and has a batting average of 32.63.
South Australian Alex Carey is tipped to be Australia's next Test wicketkeeper.