Transport commentators are worried industrial action on Auckland's rail lines will warp the census results.

Train drivers are refusing to work overtime, meaning the number of services running through most stations has been halved.

Peak-hour carriages are running very full and commuters are being urged to take other transport if they can.

Greater Auckland blog editor Matt Lowrie says it could cause some people to change their census answer on how they usually get to work.

"If we want to build light rail, or you know services to the airport and all these sorts of things, that's impacted by modelling that says if we build these services, how many people in that area are going to respond to using it."

He says it puts rail's future at risk.

"We've seen in the past with other modes and overseas and things like that as well, that when you have these types of actions, it takes awhile to build the confidence back up that the service is reliable."

However, Stats NZ says it has changed the census question to better reflect regular travel patterns.

Lowrie says the change will mitigate the issue, but it's still likely the industrial action could affect the results. 

"I guess it depends on how people answer it." 

The drivers are protesting Transdev's proposal to cut Train Managers and replace them with Transport Officers.

Transdev Managing Director Michel Ladrak says they're approaching the meeting with a compromise in mind.

"We've always offered that there is options around what the model could be, so in that sense, I have good hope that we will make a step forward, a good step forward."

However, an employment law specialist says more strikes are likely to happen after the Government pushes through a raft of law changes later this year.

Max Whitehead says the strike could be a sign of things to come if unions are handed more power under the Employment Relations Act.

"The earnings envy revolution is about to start and we are going to have a lot of industrial action laws which will allow unionist to sit in the tea room, for example, and have their full pay."