The 32 year old defender was informed earlier this week he would be in Chris Coleman’s squad and the Football Association of Wales even told Forest that their skipper had been called-up.
But Collins, who has been capped 12 times, turned down the invitation as he wants to focus solely on events at The City Ground.
The summer signing from Stoke explains: “Playing for Wales has always meant a great deal, it’s a massive honour to play for your country, but at my age I feel I would be better served to stay with Forest to train and prepare for the demanding fixtures in the Championship.
“I’m grateful to Chris for considering me but I feel it’s important I focus on Forest now.
“I would like to wish Chris and Wales all the best for the two games – I’ll be watching and hoping they can make a great start to their World Cup qualifying campaign.”