The 32-year-old goalkeeper has agreed a two-year deal at the City Ground following his release by Wolverhampton Wanderers.
De Vries won promotion to the Premier League with Swansea City in 2011 and Davies believes that the Dutchman's experience will be an asset to Forest.
"Dorus is a very good signing for us," Davies told the Nottingham Post.
"We have a good, young pool of goalkeepers at the club but he brings with him an abundance of experience which will be of benefit to everyone. He played a pivotal role in Swansea's meteoric rise through the leagues and was unfortunate not to get more games at Wolves.
"To sign a goalkeeper of his calibre on a free transfer is a great piece of business."
De Vries made 20 appearances in two years with Wolves.