A plan to ditch 8,000 diesel buses in New South Wales for an electric fleet is being delayed by at least five years.
The NSW government had initially committed to the Greater Sydney fleet going green by 2030, with the rest of the state's buses to follow, as part of its plan to achieve net zero emissions by 2050.
The promise by former transport minister Andrew Constance in 2019, was characterised as a "bold" move during a budget estimates hearing at Macquarie Street.
Minister for Active Transport, Rob Stokes told the hearing he now expected "net zero across our fleet by 2035".
"Bold goal to have 8,000 buses turned electric by 2030, that's now not the case looking at the budget," Labor MP John Graham said.
"That's correct," Mr Stokes said.
One hundred electric buses were bought in the 2021-22 financial year with another 200 purchased this financial year.
In June's budget, the NSW government committed to investing $218.9 million over the next seven years to support the move.
Mr Stokes was asked by Mr Graham whether "this is initiating the procurement process of only 1,100 buses over seven years", 6,900 less than initially promised.
"The whole point of committing to targets is to seek to reach them and then to ... 'build castles in the sky' and then go about building foundations underneath them ... that's exactly what we're doing," Mr Stokes said.
"I'm not going to criticise a former minister, but I certainly think he put out a bold goal and we're now doing that strategic work and it does appear that we're going to reach that target [8,000 buses] a little later than he suggested."
Mr Stokes said the government was currently going through the business case, which includes ensuring charging infrastructure is made available.
The NSW government confirmed outer metropolitan regions were expected to transition to electric buses by 2040 and regional NSW by 2047.
In 2019, Mr Constance said he wanted to follow the lead of London, where "drastic action" was taken after "toxic fumes" were revealed to be causing health problems.