The final phases of Zambia's digital migration project, costing the country US$273 million, is a subject of scrutiny following revelations that the cost may have been inflated.

Former minister of Information and Broadcasting Services Chishimba Kambwili raised the alarm over the cost of phases 2 and 3 of the project, currently being implemented across the country.

Kambwili has told the media the government spent US$9 million on phase 1 of the project, which covered three provinces, and questioned the cost of US$273m to migrate the remaining six provinces.

He denied being part of President Edgar Lungu's entourage to China when the digital migration deal was initially struck.

"When the decision was made by the government to single source TopStar Technologies to implement (the) digital migration project, that was the time I washed my hands. I did not play a role in digital migration and I have nothing to do with it," Kambwili said.

The former minister's revelation follows his expulsion from the ruling Patriotic Front (PF) last week.

And stakeholders, including the opposition People's Party president Mike Mulongoti, have now pushed for further investigations into the matter.

Mulongoti said he has always felt that there was "something fishy" about the engagement of TopStar and added that it was good that an insider (Kambwili) is informing the nation.

However, the Patriotic Front's deputy spokesperson Frank Bwalya said "We expected Kambwili to say what he has said and maybe he is yet to say more because the man is unreasonable and a liar. That is why we expelled him."

TopStar did not respond to requests for comment.