Melbourne commuters are being warned to planned their journey in advance today, as a train worker strike is set to grind both the city's rail network and major roads to a halt.

Metro staff are going on strike for four hours from 10:00am as part of their campaign for better pay and conditions.

Commuters have been warned of delays and disruptions all day on the rail network and VicRoads is forecasting chaotic traffic conditions as well.

Here are some of the key points to help you navigate your commute:

Trains

The strike begins at 10:00am, but Public Transport Victoria said services would begin "thinning out" before that.

"So depending on where you're travelling from your last train into the city in the morning could be as early as 8:17am," PTV performance manager Jeroen Weimare said.

A full list of the last services can be found on the PTV website.

Trains services are expected to be affected through until 3:30pm.

About 350 train-replacement buses will be running, but they will not be heading all the way into the CBD.

"I would expect from about 9:30am onwards every 15 minutes or so at suburban stations there will be a rail-replacement bus service," Mr Weimare said.

They will be stopping at locations on the outskirts of the city such as Southbank, Spring Street and West Melbourne.

So city-bound travellers will be forced to walk the last leg of the journey.

Regular bus and tram services are not affected.

V/Line

V/Line trains will be operating today but they will not stop at any metropolitan stations.

All V/Line trains will run express to and from Southern Cross Station between 10am and 2pm.

V/Line customers heading out of the city who want to board at metro stations, such as Footscray or Sunshine, will need to seek alternative services such as trams or bus replacements to get to Southern Cross.

Driving

Melbourne motorists are being warned to expect a full day of peak-hour traffic on Friday as a result of the planned strikes.

"Essentially we're looking at a doubling of travel time, at the worst, on some of the worst routes," VicRoads spokesman Nick Fisher said.

Mr Fisher said motorists should expect a full day of peak-hour traffic.

"That's what we're anticipating initially, but we're working very hard to mitigate that," he said.

All non-essential road works in the inner-city have been halted in an attempt to ease the expected congestion.

Motorists have been warned to avoid using the roads if possible.

Cycling

For those looking to beat the road and train pain on a bike, the weather bureau is forecasting a 20 per cent chance of a morning showers in the Dandenongs, but says there is a near-zero chance of showers elsewhere.

The bureau is forecasting light winds with a top of 14 in Melbourne.

Good luck!