The advertising tower on the corner of William and Wellington Streets is due to be demolished next weekend.
Transport Minister Pam Beggs today said the demolition was part of the major upgrading and improvements to Perth Station before the introduction of the northern suburbs railway.
The tower would be dismantled section by section using a 50-tonne crane.
The temporary pedestrian ramp from the Wellington Street bus station would be closed from 7 am Friday, August 21 to 5 pm Monday, August 24 while the work was underway.
Access at platform level west of platform two also would be closed during this period.
Passengers would have to use the staircase from the Alec Robinson footbridge down to Wellington Street and enter the station under the Horseshoe Bridge.
Mrs Beggs also announced the final contract to complete a major $7.6 million improvement to Perth Station had been let to John Holland Construction.
The contract, worth $1.1 million, covered paving extensive areas of the platforms, landscaping and tiling.