Mnangagwa was addressing thousands of people on Monday at the Heroes Day commemoration in Harare.
The holiday honours heroes and heroines of the liberation struggle.
Mnangagwa said one of the core reasons of waging the liberation struggle was to take back the land and redistribute it among its rightful owners.
“Let’s all take a leaf from our departed and living heroes and heroines. The land reform is finished and irreversible,” he said at the Heroes Acre.
Mnangagwa said the government however faced a challenge to modernise its agriculture sector.
“My government will continue to facilitate the enhanced processing and value addition of our resources,” he pledged.
Mnangagwa urged Zimbabweans to strive to rebuild the country to ensure every citizen was accommodated irrespective of tribe, race or religion.
The country is currently divided over the outcome of elections held on July 30.
Mnangwagwa was declared winner of the presidential poll but the Movement for Democratic Change (MDC) claims the Zimbabwe Electoral Commission rigged the poll.
A court petition by the opposition party led to the suspension of Mnangagwa’s inauguration this past weekend.
Mnangagwa urged the nation to unite and safeguard the gains of independence as unity would enable the country revive its economic challenges.
“Time for politics is over. It’s now time for action, production and service delivery. We are a bold and brave nation of warriors. Let us therefore march forward in peace, harmony and love,” Mnangagwa said.
He said that on July 30, Zimbabwe demonstrated to the world that it was capable of holding free, fair and transparent elections.
“Democracy, the rule of law and freedom have come. Like the land reform programme, they cannot be reversed,” he added.
Zimbabwe has embarked on land reforms since 2000, initiated by liberation war veterans. However, distribution has been chaotic, much to successive seasons of food shortages.