The move has been prompted by a spike in Covid-19 infection rates in Eastern Highlands Province as well as the two provinces which border with Indonesia, Western and West Sepik.
While testing for Covid-19 is limited in PNG, the delta variant was confirmed as being in the country in July, preceding a spike in patients at hospitals in these provinces, Radio New Zealand International reported.
It is understood the lockdown would begin in a week's time, and entail closure of businesses, schools and churches, and restrictions in movement.
The cabinet and PNG's pandemic advisory committee are also considering lockdowns in the National Capital District, Morobe Province and other affected parts of the Highlands including Enga.
The containment move was hinted at by Prime Minister James Marape before he flew to New York to attend the United Nations General Assembly last week.
Marape told local media that they were seeing evidence of the Delta variant spreading across the country, with people dying as a result.
With Marape now abroad, it is expected that the Acting Prime Minister Soroi Eoe will sign off on the lockdown measures.