It came as the Rail, Maritime and Transport union (RMT) was consulting its members at the train operator over potential further strikes throughout the two-week United Nations Cop26 climate change conference in Glasgow in November.
Labour transport spokesperson Neil Bibby told MSPs: “Industrial relations on Scotland’s railways are at all-time low.
“That’s a damning indictment of [ScotRail operator] Abellio’s treatment of key workers who kept Scotland moving and a damning indictment of this Government too.
"They are leading Scotland into Cop26 with growing unrest on the railways, and the prospect of strikes bringing Glasgow to a halt.
"It is a national humiliation and a failure of leadership from this Government.
"The minister must get a grip, and get a grip now.
"The Scottish Government and taxpayers are paying ScotRail for a seven day a week service and getting six days at the moment.”
Mr Bibby called on transport minister Graeme Dey to intervene in the dispute.
He said the minister should also get involved in a separate dispute involving more than ScotRail train engineers represented by the Unite union over not being offered a pay increase this year without productivity improvements.
Mr Dey insisted they were matters for ScotRail and the unions, but said he had encouraged both sides to try to resolve the situation.
The RMT dispute is over train conductors and ticket examiners being paid less than drivers for working on days off.
However, Mr Dey said the disparity was because extra conductors and ticket examiners had now been recruited to minimise such “rest day working” so higher payments could no longer be justified.
He said: “As part of agreed working conditions, all rail staff who work on a Sunday receive an enhanced payment.
"The current dispute concerns enhanced payments for working rest days.
"That arrangement, made between the RMT and ScotRail, provided an additional, time-limited enhancement for ticket examiners and conductors – largely an acknowledgment of the extra work existing staff were undertaking while ScotRail recruited and trained additional staff to minimise the requirement to work rest days.
"Now that there are 140 additional ticket examiners and conductors, the issue of excessive rest day working has been resolved.
"I understand why the unions and workers might want to make that additional allowance permanent, but it simply isn’t sustainable in the long term.
"Any cancellations as a result of industrial action not only have the potential to undermine the recovery of our rail services but also to impact on vital revenue streams from ticket sales.”
Mr Dey said total spending on the Scottish rail network had increased because of the Covid pandemic fall in passengers from £1.1 billion to £1.5bn a year, which he described as “simply not sustainable”.
He said: “What we have done is encourage the unions and management to come together in a constructive way to identify efficiencies from both sides which could be used to fund reasonable pay increases.”