"After investigations, we believe that there has been no abnormal spike in sick leave today by train drivers and [this] is another attempt by Sydney Trains to demonise their hard-working and dedicated drivers to hide their own failings", it said in a statement.
Train services have resumed between Gordon and Chatswood on the T-1 North Shore line, after lightning damaged signalling equipment.
The Rail, Tram and Bus Union (RTBU) aren't buying it though, blaming poor planning and the new timetable for the public transport operator's problems. Trains running at reduced frequency.
"We all know that we needed more trains", union spokesman Alex Classens said.
Mr Constance was asked whether he thought drivers were calling in sick as part of the union's push for a 6 per cent pay rise, but he would not be drawn on that.
On Wednesday the head of Sydney Trains, Howard Collins, admitted he had told the government that rolling out the new timetable in November would make things "tight" and said the department was "flat out" recruiting new drivers and guards.
He also slammed the new timetable, saying it was "not worth the paper it's written on".
"The problem is they've gone ahead and made promises for all these new trains when the growth trains aren't ready yet, so they've had to bring trains out of mothballs, there's no spare trains in the system and there's no spare drivers and guards, so of course it's going to be a problem when people get sick and exhausted and worn out", he said.
Mr Constance yesterday claimed the Government had to introduce a new timetable because of an 11 per cent increase in patrons in the past year. "He introduced a timetable that we were just not ready for, under-resourced, under-prepared, and now we're seeing the fruits of that".
"We've never seen those types of numbers", he said.
"This is a train service reminiscent of a Third World city", he told reporters in Sydney on Wednesday.
The City Circle includes Central - Australia's busiest railway station - as well as the heaving inner-city stops Town Hall and Wynyard and the tourist and business hub of Circular Quay, among others.
They said the NSW Government was "solely responsible" for the "chaos".
Bayliss will not coach England past 2019
England's Mark Stoneman avoids a high delivery from Australia's Mitchell Starc during their Ashes cricket test match in Sydney. Things were no better for Stoneman. "There's so much cricket now it is hard to be playing in all formats", said Bayliss.
Massive 146-inch TV introduced by tech giant
The Consumer Electronics Show kicks off at the end of this week and we will come again with the last CES news for you. For the uninitiated, the pixels on a MicroLED module are significantly smaller than a conventional LED display.