[1] As Minister of Environment in Fico's Second Cabinet, Žiga was investigated for suspicion of stealing the property of state forests, at the expense of which his private company profited.

[3] When Peter Pellegrini took office as president of Slovakia on 7 April 2024, Žiga was entrusted with the function of Chairman of the National Council of the Slovak Republic.

[4] Since becoming Minister of the Environment, Žiga has been investigated for corruption related to state-owned forests, from which his own private company is alleged to have benefited.

[5][6] The current government, elected in 2020, has launched investigations into several cases dating from during Žiga's tenure at the Ministry of the Environment, including alleged theft of public funds and Eurofunds, signing of unfavorable contracts for the export of timber, and channelling of millions in European Union subsidies to companies connected with Smer-SD.

[7] In 2016, Žiga was ranked among the 40 most influential people in the Slovak energy sector by Euractiv.