The 30-year-old has been performing exceedingly well in Test on home turf, averaging 60.11 per innings against the new ball, which is the highest by any player to have worn the Baggy Green Cap as a regular Test opener in Australia.
While he is a dominant performer playing Test at home, his average drop to 37.40 when he opens the innings outside Australia while , his form significantly drops when he bats in Asia, averaging 30.38 - nearly half of his performances Down Under
However, Lehmann expressed confidence that Warner would surely going to turn his form around on the subcontinent.
"I think he's realised what he can and can't do. I'm pretty confident that he's going to turn his form around on the subcontinent. He looks good from what I've seen of him so far, and he got starts in India (earlier this year) without going on," cricket.com.au quoted Lehmann as saying.
Lehmann, who is in Darwin where Australia's 14-man squad for the Bangladesh series has gathered for a week-long training camp, insisted that it is necessary for him as well as for the team to score big in Bangladesh.
"If he goes on, then we'll have a really good series in Bangladesh. So for him, and for the team, we need him to make big runs as he normally does (in Australia)," he added.
In Australia's most recent Asian visit to India, Warner's top score was 56 during the first innings of the final Test of the three-match series, which home team went on to win by 2-1.
Australia are slated to play a two-day warm-up game in Fatullah on August 22 and 23 before heading into the first Test.
It should be noted that tour got its green signal following the resolution of the contracts dispute between Cricket Australia and the Australian Cricketers' Association.
Australia squad for Bangladesh series:
Steve Smith (c), David Warner (vc), Ashton Agar, Jackson Bird, Hilton Cartwright, Pat Cummins, Peter Handscomb, Josh Hazlewood, Usman Khawaja, Nathan Lyon, Glenn Maxwell, Matthew Renshaw, Mitchell Swepson, Matthew Wade.(ANI)