THE HISTORY OF MYKI:

* July 2005 - The Victorian government signs a contract to get myki built and operating. The system is meant to be up and running in two years

* December 2008 - The rollout is marred by delays. Myki is implemented on buses in Geelong

* 2009 - The system is extended to buses in other Victorian regional centres, before it is also rolled out on Melbourne trains

* July 2010 - Myki is implemented on Melbourne trams and buses

* December 2012 - Melbourne's previous ticketing system, Metcard, is switched off, leaving myki as the only option on the city's public transport

* 2014 - Myki is extended to V/Line services. Public Transport Victoria pays back more than $1 million after criminals stole money from foreign credit card holders to buy myki cards, before onselling them to commuters via the black market for a reduced price

* June 2015 - An auditor-general's report into myki finds Public Transport Victoria still can't tell if the system is performing adequately, despite costs blowing out by $550 million

* August 2015 - Public Transport Victoria has paid back $4.2 million to foreign credit card holders caught up in the myki scam

* September 2015 - The company behind Sydney's Opal transport card rollout sets up in Melbourne in a bid to take over myki

* December 2015 - The Victorian government announces a sweeping review of the myki system amid concerns about the legality of on-the-spot penalties on public transport

* July 2016 - Victoria hands a $700 million contract to the company that built the myki system, NTT Data, to run it for another seven years. The then-public transport minister says the government would investigate making it possible for passengers to tap on with their credit cards or smartphones

* September 2016 - Melbourne's Metro rail network is voted the worst in Australia for the fifth year running

* June 2017 - It's revealed the government renewed NTT Data's $700 million contract without doing a review of the much-maligned myki system

* 2019 - The Victorian government announces up to 4000 commuters could be part of a trial into Android-supported technology to buy a public transport ticket, add money and touch on and off using their phones

* December 2022 - The Victorian treasurer says the failed myki system will be reviewed ahead of the existing contract ending in November 2023

* May 2023 - US company Conduant is announced as the winning bidder to overhaul the ticketing system to eventually introduce tapping on and off with iPhones and credit cards