Tamim has been rested for the tournament due to neck strain while Shakib has been suspended for three games for making obscene gesture on camera.
"Bangladesh are a fantastic one-day team. They had a couple of close games against Sri Lanka. Everybody knows that they are a very good one-day unit," Karthik told reporters on the sidelines of team's practice at the Sher-e-Bangla National Cricket Stadium here.
"Definitely we all know they are a good one-day side and we will give them a lot of respect," Karthik said of Bangladesh who won 3-0 in a series against New Zealand before going down to Sri Lanka by an identical margin.
On the absence of Tamim Iqbal who has been ruled out because of a neck strain and the suspension of Shakib, the 28-year-old said: "Tamim and Shakib are major players for Bangladesh. They are going to be replaced by two peoples who we may not know much."
It's a venue where Bangladesh have happy memories of chasing down New Zealand's 308 with four wickets in hand but Karthik said they're geared up to the challenge.
"Except Bangladesh I don't think many teams would have played there... That's part of International cricket that you don't get to play in all the venues. It's one of those occasions for us it's going into a new venue and we're starting fresh. Having said that, we will go all guns blazing and do our best," Karthik signed off.