The decision to commit additional money to the route is a direct response to the recent closure of the A55 due to flooding as a result of heavy rainfall and high winds.
Following the closure the Minister ordered an urgent review to identify lessons learnt from the incident, establish the way forward and consider potential improvements.
The initial stage of that review has now been completed and further work will identify the prioritisation of future drainage works and schemes.
Carl Sargeant said:
"The A55 plays a vital role for the economy of North Wales."
"Ensuring that this essential route meets the needs of local businesses and residents in order to improve the local economy and regenerate the surrounding areas is paramount.
"The recent closure of the A55 due to flooding is unacceptable and we will be doing all that we can to avoid similar situations arising in the future.
"This additional money will help address the risk to the route, by enhancing the capacity of the existing infrastructure at known problem spots, whilst longer term work is planned."
This comes on top of increased spending with regard to drainage maintenance in recent years in North Wales, of £1.16m in 2011/12 and £0.65m this financial year.
In addition to these works, investment has continued to improve lighting in the Conwy tunnels, CCTV coverage along the A55 together with driver information signs (VMS) and improvements to winter service to improve resilience and reliability of journey times not only on the A55 but throughout the trunk road network.