Scotland and Netherlands join Bangladesh in Group B for the tournament in Australia scheduled for October and November 2020
Ireland have been rewarded for reaching a sixth consecutive T20 World Cup with a meeting with 2014 winners Sri Lanka in the first round group stage of the 2020 competition.
Gary Wilson's side were among six nations to book their place in the tournament in Australia during the qualifying tournament in the United Arab Emirates.
Sri Lanka missed out on qualification for the Super 12 stage virtue of their world ranking and will face the Irish in the opening game of the tournament on October 18.
Papua New Guinea, taking their place in their first-ever major tournament, and Oman, complete Group A.
Bangladesh, another Test-playing nation forced to go through the preliminary stage, are joined by Scotland, Netherlands and Namibia in Group B.
Following the round-robin format, the winners and runners-up of each group will join the eight sides who have already secured direct passage to the Super 12.
Hosts Australia are joined by Pakistan, New Zealand, West Indies, India, England, South Africa, Afghanistan in the competition proper.
First-round fixtures
Oct 18: Sri Lanka v Ireland, Kardinia Park, South Geelong (2pm local); Papua New Guinea v Oman, Kardinia Park, South Geelong (7pm)
Oct 19: Bangladesh v Namibia, Bellerive Oval, Tasmania (2pm); Netherlands v Scotland, Bellerive Oval, Tasmania (7pm)
Oct 20: Ireland v Oman, Kardinia Park, South Geelong (2pm); Sri Lanka v Papua New Guinea, Kardinia Park, South Geelong (7pm)
Oct 21: Namibia v Scotland, Bellerive Oval, Tasmania (2pm); Bangladesh v Netherlands, Bellerive Oval, Tasmania (7pm)
Oct 22: Papua New Guinea v Ireland, Kardinia Park, South Geelong (2pm); Sri Lanka v Oman, Kardinia Park, South Geelong (7pm)
Oct 23: Netherlands v Nambia, Bellerive Oval, Tasmania (2pm); Bangladesh v Scotland, Bellerive Oval, Tasmania (7pm)