The Maritime Union is confident it can work with Ports of Auckland to keep job losses to a minimum in the wake of automation.

Ports of Auckland has announced it will shortly begin work to partially automate its container terminal to increase terminal capacity, but up to 50 jobs could be on the line.

But Union National Secretary Joe Fleetwood said they're in ongoing, robust discussions with Ports of Auckland, and the automation hasn't come as a surprise.

He said it's still early days and the union is well-represented at the negotiating table with the Auckland.

"This isn't going to be an overnight process. We are probably looking in the vicinity of 2019 before it can fully come into fruition. There's going to be a lot of trials and tribulations but at the end of the day, you can't fear automation."

Fleetwood said the focus is ensuring as many staff are upskilled or redeployed.

He said their workers should be given the first job to retrain into new roles, or given training to move on if they wish.

Fleetwood said it's important is to keep discussions with the Port going, because "you're not in the ball game if you're not in the park".