Zulu King Goodwill Zwelithini has called on President Cyril Ramaphosa to exempt nearly three million hectares of royal land from the government's redistribution plans.
Land expropriation without compensation has become a hot topic in South Africa after Ramaphosa vowed that the country's constitution would be changed to explicitly allow for the expropriation of land without compensation.
The policy is designed to redistribute land to poor black people to tackle severe inequality 24 years after the end of apartheid, but it has attracted sharp criticism.
"He (Ramaphosa) must come here... and say it, write it down in an agreement and sign off that the land of the Zulus will not be touched," Zwelithini said in speech on Sunday.
"As the Zulu leader, I am trying to ensure that your things are protected and go well," he told cheering crowds.
Zwelithini is the sole trustee of 2.8 million ha (6.9 million acres) of land through the Ingonyama Trust although the land does not belong to him.
He has previously warned that "all hell will break loose" if the trust's ownership was challenged.
Land reform is set to be among the fiercest political battlegrounds at elections next year, when Ramaphosa will try to revive fading support for the ANC, which has ruled since the end of apartheid in 1994.
Ramaphosa has vowed reforms will be within the law and not threaten stability, but many landowners and investors remain alarmed by the policy.
Kings have no official power in modern South Africa, but still command loyalty among millions of people.
They are recognised in the constitution as traditional leaders and receive government funding.