The message said the company would"offer you and a friend a free bike each as a sign of our gratitude for your loyalty and support"to users who didn't want to transfer their membership.
University of Technology graduateDonald Tang launched the start-up with 160 bikes for hire last July.
In a statement ofo it had"made a strategic decision to focus on priority markets internationally"and would wind down operations in Sydney and Adelaide in the next 60 days.
The company will begin to remove bikes from the streets and shift them to its warehouses.
"This decision does not come lightly,and ofo Australia will act responsibly in each market as it winds down operations,resolving any outstanding concerns before finalising operations."
Meanwhile,the future of oBike in Sydney remains unclear,after the company abruptly stopped operations in Melbourne and Singapore earlier this year.
The company decided to withdraw from Melbourne rather than meetstrict new rules imposed by Victoria's Environment Protection Authority.
The Singaporean business,which rolled out 1000 bikes in Sydney last August,last month appeared to still be operating in Sydney. OBike could not be reached for comment.
Mobike Australia general manager Mina Nada,who launched the operator in Sydney last November,said the share bike industry still had"huge potential"in Sydney.
“People have really taken to using the bikes to get around the city and in particular with commuters getting to and from work."
Clr Scully said dockless bike share had been"phenomenal in terms of increasing the number of people cycling",accounting for 6600 trips in Sydney each day with 140,000 registered users.
She said dockless bikes were positive as they cut traffic congestion and provided more transport options but admitted"there were certain teething issues with the introduction of these services".
A"state-based approach"to regulating the industry made sense given bike users often travelled between local government areas,she said.
Six inner Sydney councils joined to impose new guidelines on bike share operators to clamp down on haphazard placement of dockless bikes in parks and streets last year.
The NSW government said in May it would give councils bolstered powers to deal with dumped share bikes under a new code of practice targeted at operators.
The withdrawal of the bike share companies comes after ride-hailing company Uber said this week it wouldadd motorised scooters to its mobile app after it invested in California startup Lime.
Sun Sheng Han,professor of urban planning at Melbourne University,said the future of shared bikes in Australia was uncertain.
But he said the companies'exits could be viewed as"a retreat in the broader picture"and a reflection of their rapid expansion and venture capital-driven business model.
Professor Han said some schemes could survive due to a desired cultural shift away from car travel towards public and active transport.
"On the other hand,changes in infrastructure,regulations and civic culture need time,probably a long time,which provides opportunities for more experiments,debates and policy innovations."