The National Union of Mineworkers is preparing to take President Cyril Ramaphosa and the state to court over plans to restructure Eskom.

The National Union of Mineworkers (NUM) is preparing legal action against President Cyril Ramaphosa and the state over plans to restructure Eskom, saying the process could threaten the utility and the broader economy.

The NUM's national executive committee, its highest decision-making body between national congresses, took the decision at a meeting in Pretoria from August 5-7.

The union's decision follows Ramaphosa's endorsement last month of the Phase I report of the Eskom Restructuring Task Team, which clears the way for the creation of an independent, state-owned Transmission System Operator (TSO).

The proposed TSO is intended to separate Eskom's transmission function from the rest of the utility and form part of efforts to create a more competitive electricity market, attract investment, reduce electricity prices and strengthen energy security.