The announcement was made at a meeting of the A83 Task Force in Arrochar today, 25 January.
A further £6.6 million will be invested in the route, with just over £4 million for the landslide mitigation measures at the Rest and Be Thankful.
The work programme includes widening the Old Military Road to add resilience to the local diversion route.
In addition, further enhancements will be made to the debris netting which has prevented 2,300 tonnes of debris reaching the route since its introduction.
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The extra finance is being provided by Transport Scotland in addition to the £3 million already committed to the 2015/16 programme.
Overall, total investment in landslide mitigation at the Rest and Be Thankful is £13.5 million.
Transport Minister, Derek Mackay said: "More than £50 million has been invested in the A83 since 2007 underlining the Scottish Government’s commitment to keeping Argyll and Bute open for business.
"The most recent landslides have shown that the mitigation measures introduced, including netting, catchpits and culverts, are doing their job with thousands of tonnes of debris being caught on various occasions.
"The elements have thrown some horrendous conditions our way, especially at the end of last year with the wettest December on record. We are already learning lessons from the events that occurred as a result of the exceptional rainfall and the additional investment being outlined today will help strengthen our response further."
(LM/MH)
