“The Cameroonian Football Federation (Fecafoot) is invited to take the necessary measures for a rapid and harmonious implementation of these very high directives.”
The appointment would be unusual because Fifa rules require any member association to be independent and avoid any form of political interference.
Conceicao had led Cameroon to World Cup qualifying play-offs and they will play Algeria in a two-legged tie in March for a place at Qatar 2022.
Song, who also played for West Ham in England and had spells in France, Italy, Germany and Turkey during his playing career, also featured at four World Cups and won the 2000 and 2002 Africa Cup of Nations titles.
Song will be assisted by the former Congo-Brazzaville, Kenya and Equatorial Guinea coach Sebastien Migne. The Frenchman, whose most recent job was at South African club Marumo Gallants, led Kenya to the 2019 Africa Cup of Nations finals in Egypt.
The technical team also includes for internationals Souleymanou Haminou as goalkeeper coach and Raymond Kalla as team manager.
BBC Sport Africa’s Nick Cavell
It is unclear whether the statement from Cameroon’s sports ministry about the change in coaching staff was simply confirmation of a request from Fecafoot or a directive to the body led by Samuel Eto’o.
Conceicao was the Cameroon coach when Eto’o was elected as Fecafoot president in December, less than a month before the start of the Africa Cup of Nations on home soil.
The Portuguese coach’s job was questioned after the hosts lost to Egypt on penalties in the semi-finals but a dramatic third-placed finish seemed to ease the pressure on him.
However just three weeks later Conceicao has lost his job to be replaced by Eto’o’s former international team-mate Song with the phrase “On very high instructions from the President of the Republic…” in a letter from the ministry causing controversy.
Fifa frowns on government interference in football but the appointment of coaches – especially across Africa – is often a bit of a grey area since the majority of associations rely on the government to pay at least part, if not all, of the salaries for technical teams.
The governing bodies usually recruit the coaches but need the ministry’s approval for the contracts offered, and often to cover the compensation for anyone who is sacked before the end of their deal.