Sydney commuters have faced delays as an already reduced public transport timetable is hit by ongoing industrial action.
Members of the Rail, Tram and Bus Union are taking industrial action over the next two weeks, with bans on overtime, working with foreign rolling stock and alongside contractors.
NSW Transport Minister David Elliott planned to meet with the union on Monday to try and resolve the long-running dispute over a new enterprise bargaining agreement.
"Some of their claims are legitimate and some of them are quite bizarre," he told Sydney radio 2GB on Monday.
"Frontline workers deserve a pay rise but what workers deserve and what taxpayers can afford are two different things."
The union's refusal to work on foreign-made rolling stock was "extraordinary", as was the ban on overtime, which would only hurt the rank and file members' families, he said.
Sydney Trains executive Matt Longland also told 2GB the overtime ban was causing delays after a signaller on the T8 Airport & South line fell ill and was unable to be replaced.
A Sydney Trains spokesperson said buses were used between Holsworthy and Turrella from 7am until 1:20pm on Monday, and "flow on delays" hit customers on the T2 Inner West & Leppington, T3 Bankstown and T5 Cumberland lines.
"Overtime gives us the flexibility needed to be able to manage a large and complex network efficiently and is used to cover things like COVID-19 sick leave," the Sydney Trains spokesperson told AAP.
RTBU NSW secretary Alex Claassens said transport had known about the industrial action for weeks.
"If they'd done their jobs and rostered properly, this shouldn't be causing a headache for anyone else," he said.
"We'd hoped that after the industrial actions taken last year the government and transport bureaucrats had finally agreed to listen and negotiate.
"But time and again they've refused to put basic safety provisions in place to ensure that commuters and workers are kept safe on our railways."
RTBU organising director Toby Warnes told members last week that despite "many months of bargaining" since the enterprise bargaining agreement expired in May, management for Sydney Trains and NSW TrainLink were "still failing to show members and delegates the respect that they deserve".
Mr Warnes said after ignoring union requests to ensure safety and hygiene were protected while giving drivers an overdue pay rise, management were now seeking to put changes "into policy rather than into the enterprise agreement".
"Policy can be changed at the whim of management, whereas an enterprise agreement is legally enforceable by members," Mr Warnes says.
Transport for NSW says negotiations are ongoing but have reached "a number of concessions already ... which could be included in a final agreement".
There had been six meetings between the rail operators and the unions already this year, on top of more than 30 negotiations last year.
The industrial action will continue until February 21 and is expected to cause delays and cancellations on the Sydney Trains, NSW TrainLink Intercity and regional train networks.
Some regional trains could be replaced by buses.
