Concern Auckland's rail issues are a 'bit muddy' with a lack of clarity around the sudden drove of cancellations.

Auckland Transport has limited services yesterday and today due to 'heat' affecting track steel.

The Public Transport Users Association's Jon Reeves says he's heard claims some work KiwiRail was meant to do over Christmas to prepare trains for heat wasn't done.

He says coincidentally, the issues have emerged after the holiday closures.

"I don't think everyone's been clear to the media or the public what the issue is, but the end result is- Auckland train users are really having a bad summer."

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