PNG won the toss and chose to bat first and finished on 154 for five, with Assad Vala top-scoring with 55 before being caught and bowled by Hamza Tahir.
The Scots powered towards their target within 18 overs, with George Munsey leading the chase before being caught on 50. Richie Berrington (41 not out) and Callum MacLeod (27 not out) saw them over the line on 156 for two.
Head coach Shane Burger also had praise for debutant Chris Greaves, who bowled four overs including one for 17.
“I am really happy for the team to get another victory, winning becomes a habit and we are doing well at the moment, at times we do make it tough for ourselves and we are still searching for the perfect game, but that will come,” he said.
“Highlights for me in this game were the way that the spinners bowled on a surface that didn’t always help them, they were superb and Chris Greaves on his debut showed what he is all about.
“And the batters were very professional, they batted how they needed to to get the team over the line.”
Munsey added: “It is really hot out here, so to get over the line in a game like this is testament to all the hard work that everyone is putting in on and off the pitch and everyone mucked in during this game.
“PNG had the better of us in the powerplay, but for the bowlers and the fielders to battle back and keep them to what we felt was just a below par total showed character.
“With the bat it was important that we got off to a good start and myself and Kyle managed to do that and then Oli, Richie and Calum came in and showed that same intent.
“It was nice personally to get some runs, but most important was the win.”
Scotland face Namibia in another warm-up fixture on Saturday before their opening T20 World Cup first-round match against Bangladesh in Oman on Sunday week.