The English-born Wales U21 international comes out of contract at the end of the season but has done enough in his two loan spells with the Saints, which includes the League Cup triumph, to win a Toon extension.
"I think Newcastle are going to offer me a new deal. It seems they want to keep me. My contract with the club ends in the summer, but the indication is that I'll stay on," Dummett told the Sunday Sun.
"I'm not exactly sure what is going to happen, but I would hope to report back in the summer to the club and I'll be coming back a much better player for my year with St Mirren.
"My hope is to break into the Newcastle team and I'll be out to impress the manager in training.
"The manager asked for (fellow Magpie loanee) Conor (Newton) and myself to come in and see him so he could congratulate us (on the cup win), which was a brilliant gesture."