The Australian Workers Union says its members who are race day officials may take industrial action, although the Melbourne Cup won't be affected.

Victorian race day officials are threatening to take industrial action that could lead to races being delayed or cancelled, although the Melbourne Cup will not be affected.

Australian Workers Union members have voted to take action during the spring racing carnival, amid stalled negotiations with Racing Victoria over a new enterprise bargaining agreement.

It is understood the stop-work action may involve barrier attendants.

AWU Victorian secretary Ben Davis said whether the race day officials went ahead with the protected action would depend on any talks with Racing Victoria over coming days.

"There is the potential that it will impact on races," Mr Davis told AAP on Saturday.

"Potentially races could be delayed or cancelled."

The union has to give three clear working days' notice of any action and Tuesday is a public holiday in Victoria, meaning most of this week's Melbourne Cup carnival will not be affected.

Racing Victoria spokesman Shaun Kelly said the earliest the officials could take protected action would be Friday.

He said race meetings at Flemington and across the state on Melbourne Cup day and Oaks Day on Thursday will be unaffected.

"Given the AWU represent a small percentage of our race day officials, we have a contingency plan in place to ensure that all feature meetings can proceed as scheduled so that owners, trainers, jockeys and racing fans are not impacted by their proposed action."

Mr Davis said race day attendants had been frustrated by the lack of progress in negotiations for a new EBA since March.

"They don't consider doing what they're doing lightly at all.

"At this point they don't feel like they've got a lot of choice."

Mr Davis said there had been an increase in twilight and night races and the officials believed they should be paid "a little bit extra" for that work.

Mr Kelly said it was disappointing the AWU had chosen to take advantage of the spring racing carnival to threaten industrial action, adding Racing Victoria had been in good faith discussions with the union as late as Thursday.

The Melbourne Cup carnival kicked off with Derby Day on Saturday and ends next Saturday with Stakes Day.