Hungary's opposition party Fidesz has warned of "tyranny" in government after Prime Minister Peter Magyar submitted an amendment to remove President Tamas Sulyok, which could come into effect as early as next week.

Fresh off an April landslide that ended former leader Viktor Orban's 16-year rule, Magyar has repeatedly pressed to remove the predecessor-appointed president, whom he calls "Orban's puppet".

In an amendment filed on Saturday, Magyar stipulates that "the mandate of the incumbent President of the Republic shall terminate on the day following the entry into force of the amendment to the Fundamental Law".

With a parliamentary supermajority, the governing Tisza Party is expected to pass the amendment.

As reported by Euronews, the Fidesz party has called for a demonstration on Thursday in support of Sulyok.