United face a lengthy trip to Wales to take on the League Two outfit at Rodney Parade (kick-off 5.30pm BST) with the opportunity to reach the last eight of the competition for the first time in four years.
Newport, though, knocked out Championship side Watford in the previous round and have performed a number of notable cup upsets in recent years, beating the likes of Leeds United and Middlesbrough along with holding Tottenham Hotspur to an impressive draw.
Bruce said: "Over the last few years they've been the team in the lower divisions who have produced a shock. Whether it's in the FA Cup or Carabao Cup, they're a good side. I watched their performance at the weekend and the one before that when they beat Watford.
"They play the right way, play three at the back and try to play through you and Michael Flynn (Newport's manager) has done a wonderful job there in difficult circumstances. Make no mistake, we've got to approach it right because it is a difficult place to go with or without fans because of what they have got on the pitch.
"They're really dangerous opponents and we have got a wonderful opportunity but know what we're up against. They are a decent team who are flying high in the league at the minute, playing well and I've been impressed with what I've seen."
The Magpies, however, will be without the services of Matt Ritchie, who suffered a shoulder injury in Sunday's 1-1 draw at Tottenham after a collision with defender Matt Doherty, with the injury deemed to be similar to Fabian Schär, also sustained against Spurs in July.
Although Ritchie is likely to miss a number of weeks, fellow Scotsman, Ryan Fraser, is in line to feature against County tomorrow night after missing out on Sunday's trip to North London.
"Matt is seeing the surgeon today and it's a very similar injury to Fabian Schär," Bruce added. "A disruption of the shoulder joint. How unfortunate are we? To have one is bad enough but two in a matter of weeks is incredible. It looks as if he'll need an operation and it'll be performed fairly soon.
"It's been around nine weeks out now but Fabian's ahead of schedule and doing well. We have to be a bit careful. He wants to join in and play but we're guided by doctors on him. We'll see how it is but we're looking at a lengthy lay-off (for Matt Ritchie).
"That along with (Paul) Dummett and the long-term injuries of Matty Longstaff and Ciaran Clark is a concern that we have these injuries. Obviously you cannot prevent as it's a physical game but we've had our fair share of bad luck with it.
"Ryan (Fraser) trained well yesterday. I think it was the right call (to leave him out against Tottenham Hotspur) so we'll see how he trains today but he's in contention for tomorrow night."
Goalkeeper Mark Gillespie will be targeting another appearance in between the sticks for his boyhood club on Wednesday night, with the 28-year-old shutting out Blackburn Rovers and Morecambe in rounds two and three respectively.
Bruce expressed his delight at the shot-stopper's performances in the competition, following his arrival on a three-year contract in July.
"Very quietly, he's got on with it and kept two clean sheets," Bruce added. "It was a big night for him against Blackburn. The club he played for as a boy released him and he went away to learn his trade, came back and the opportunity has arose very quickly for him.
"He's kept back-to-back clean sheets and done nothing wrong so let's hope that continues for him. I'm delighted for him because out of the five signings (this summer), he's the one which has sort of slipped under the radar but he has performed well."
