Papua New Guinea (PNG) superannuation operator Nambawan Super Ltd says about 1000 families will have to move from the Bush Wara settlement in Port Moresby by mid-July.
Chief executive Paul Sayer said in total about 5000 people would be affected.
The company, which has owned the land for more than 30 years, is planning a complete a new suburb on the more than 200 hectare site.
It values the site at 90 million kina or about US$23 million.
The company said it has court approval to issue Writs of Possession to the illegal squatters at Bush Wara.
Sayer said Nambawan Super is planning to follow on its original plan for the site from 1990.
"It's not just looking at housing but also there would be a development there to accommodate a community that's being built. So things like shopping centres, to have potentially.
"So commercial, as well as then parks, and we are looking at things like schools and the other facilities that would be normally required in a community."
Sayer said first up the company needs to get vacant possession after which it can review and assess the land.
This would mean "a lot of work understanding things like the runoff [and] how water works," he said.
"We also need to look at where the infrastructure will go through and then we need to follow through each of those particular developments."
He said for Nambawan a key part is the need for "Port Moresby to have housing and that's one of the big drivers we're trying to do with this is actually start to get some work happening towards looking at how can we get those assessments done and look at the return [to members]."
Sayer said before it asked the squatters to leave it undertook a social mapping of the block and it knows there are about 1,000 families there.
But he said the company has been telling them over the past three years that they would have to move on.