Mark Drakeford said the impact of the cost-of-living crisis came up in conversation with Charles during their audience on Friday, after the new monarch addressed the Welsh Parliament for the first time as sovereign.
The First Minister said the King also told him he was interested in renewable energy generation in Wales, and how it might play a “bigger part” in future energy security.
Mr Drakeford told TalkTV: “The King has always had a very direct interest in the things that are happening in contemporary Wales, the future of our agriculture, the impact of climate change.
“He mentioned the impact of the cost-of-living crisis and how that will impact on people here in Wales.”
He added: “He (Charles) is concerned as to how people will manage through what is going to be a difficult winter.
“He was interested to tell me about some of the projects that he has heard of, or become involved in dealing, for example, with food waste, making sure that we don’t waste a precious resource when some people might be going without.
“Interested, as always in renewable energy generation here in Wales, and how it might play a bigger part in future energy security.”
Mr Drakeford has suggested the investiture proceedings for William, the new Prince of Wales, need not follow the same form as that of the 1969 ceremony that saw the title bestowed upon his father.
He told TalkTV: “Well, I certainly don’t think that 1969 is a good guide for what should happen in 2022. Wales is a very different place.
“The nature of the monarchy has developed over that period. My message is that we shouldn’t be in a rush about all of this.
“We should allow the new prince, as I say, to become familiar with his new responsibilities, develop the job in a way that will work for him and will work for Wales.
“And then we can think about how and whether there is a need for any further ceremonial underpinning of what has already been announced.”