Sydney rail union leaders are considering their next move after a ballot gave the green light for potential industrial action during a pay dispute.
NSW Transport Minister Andrew Constance on Friday urged workers not to resort to "unnecessary" strike action and put customers first following a chaotic week of mass cancellations and delays.
The network went into meltdown at the beginning of the week and although the problems were initially blamed on drivers being sick and storm damage, it's also been revealed excess leave was approved.
The Rail, Tram and Bus Union on Friday said the option of industrial action was live after an "overwhelming majority" of workers who took part in a ballot voted in favour.
The workers have been pushing for a pay rise of six per cent each year but the government is firm in sticking to a 2.5 per cent cap.
"The government will agree to a pay rise for train drivers in accordance with the wages policy - a policy that applies to teachers, nurses, police and all public sector employees," Mr Constance said in a statement.
The minister also claimed the ballot result was not the clear-cut majority union bosses were hoping for because about 3000 people voted for strike action out of a workforce of 9550.
RTBU NSW Secretary Alex Claassens said passengers would always be given as much notice as possible ahead of any action.
"Industrial action is always a last resort," he said.
"Management are in a position to avoid that situation and we're still very hopeful they'll come to the table and negotiate a fair and reasonable offer before we get to the point of action."