The announcement comes as work at the Rest and Be Thankful pass is nearing completion.
The funding will be channelled into other landslide risk areas on the road.
Investigations have been completed at Cairndow and Loch Shira as well as at Glen Kinglas. The cash will also be spent on other maintenance schemes on the A83, such as the Strone Point realignment and the trunking of the A83 from Kennacraig to Campbeltown.
Transport Minister Keith Brown said: "In the last seven years, the Scottish Government has invested more than £32 million on the A83, a clear acknowledgement that it is a lifeline route for communities.
"We want the road to remain operational, whatever the conditions, and we have made landslide mitigation our priority.
"Solutions are being delivered by Transport Scotland, with almost £8 million spent around the Rest and Be Thankful in recent years. Debris fences at this location have made a positive difference and the local diversion route along The Old Military Road has been used successfully.
"The A83 Route Study has recommended actions to address landslide hazards at other locations and this funding will allow us to take forward a programme that will achieve a similar level of residual risk from landslides that we have achieved at The Rest."