Analysis of samples from its remote sites near the border with Mozambique "definitively proves the presence of hydrocarbons in multiple reservoir pay zones" at one of the wells.
It said analyzed samples "demonstrate a consistent, high-quality natural gas composition, exhibiting low inert content, containing less than" one percent carbon dioxide.
The discovery comes 30 years after US giant ExxonMobil gave up its quest to secure crude oil in the area.
The find could lead to Zimbabwe's first gas production and help improve power supplies in a country plagued by dire electricity shortages.
Zimbabwe suffers severe power outages of up to 19 hours a day.
Invictus Energy signed the exploration, development and production deal with Zimbabwe in 2018.
It plans to build a gas-to-power facility to supply the national grid.
The find is also a boon for President Emmerson Mnangagwa's government which is entitled to as much as 60 percent of the project's output under an agreement with Invictus Energy.
The site contains the largest undrilled structure in inshore Africa according to the Australia Stock exchange-listed firm.
Exploration started in August some 200 kilometers north of the capital Harare at a field that is estimated to hold 20 trillion cubic feet of gas.
New Petro Find in Zimbabwe
HARARE - Australian oil and gas firm Invictus Energy announced Monday it has found light oil, gas and helium in remote northeastern Zimbabwe, a culmination of months of exploration.
