War veterans have accused Grace of having too much influence over her 92-year-old husband.
As President Robert Mugabe shows signs of frailty, senior members of the ruling Zanu PF party are positioning themselves for the post-Mugabe era.
Two factions have emerged, one linked to Vice-President Emmerson Mnangagwa and one to Mugabe’s wife.
The newspaper supplements hailing Grace, which were the first in Zimbabwean State media for anyone’s birthday but the president’s, ran gushing messages of praise from government ministries, including defence, as well as loss-making State companies.
“Dr Grace Mugabe: A woman who conquered Africa,” read a headline in The Herald newspaper, reflecting the growing political influence of the First Lady since her appointment to the top leadership of Zanu PF in 2014.
“A loving mother, compassionate philanthropist, astute businesswoman, perceptive politician, remarkable patriot,” the State-owned daily wrote.
Even government departments and State-owned companies that have been failing to pay their workers splashed money on advertising space to congratulate Grace.
The political infighting in Zanu PF has been exacerbated by an economic crisis, widely blamed on mismanagement and, more recently, the effects of a scorching drought in the region.
Public anger over inflation, unemployment and other hardships has poured out into the streets in a nation-wide protest movement.
“[Mugabe’s] leadership has presided over unbridled corruption and downright mismanagement of the economy, leading to national economic ruin for which the effects are now felt throughout the land,” war veterans said in a statement last week as they withdrew their support for the 92-year-old leader,“The president and his cohorts… have slowly devoured the values of the liberation struggle.”
Mugabe has claimed Grace is not interested in taking over his position when he finally leaves the scene, but this has been contradicted by the First Lady’s public pronouncements and manoeuvering in Zanu PF.