ADELAIDE Railway station will be closed to all train services for at least a month because of convention centre renovations and rail line electrification.

As revealed on AdelaideNow yesterday, the work - expected to begin in January - means passengers will have to be bussed between city from inner-suburban stations.

The closure will affect tens of thousands of commuters and also restrict traffic along the Morphett St Bridge.

The State Government has told the Rail, Tram and Bus Union that the work will begin in the first week of January.

Convention centre project and TransAdelaide sources also have told The Advertiser that the start date is January 2.

A government spokeswoman said a date "had not been confirmed", but said "January and February would be the best time", given the lower user numbers during the summer holidays.

And Transport Minister Pat Conlon has written to station and arcade traders, saying "there will be a need to suspend train services to the Adelaide Railway Station for a period of approximately one month".

Rail union state secretary Ashley Waddell said he was told by the Transport Department that "train services won't be running into Adelaide Railway Station" early in the New Year.

The department also told the union at a June meeting it planned to end the northern line trains at North Adelaide and the southern services at Goodwood, Mile End or Keswick, Mr Waddell said.

No terminal station had been decided on for the western services at the time of the June meeting, he added.

The Advertiser also has been told the Noarlunga line will be subject to months of electrification work from January, affecting the line from the city to Oaklands Park station.

A Transport Department spokeswoman confirmed more work would be carried out on the line, but said no dates were available.

The majority of voters in an online poll on the AdelaideNow website said they didn't know how it would affect their travel plans, while more than a fifth said they drive and fewer than 20 per cent said they would use the shuttle bus service.

Opposition transport spokeswoman Vickie Chapman said she was approached this week by station traders who were worried about the impact on their businesses.

"They wanted to know why the whole station had to be shut down," she said.

Originally published as All aboard for rail chaos