The Scottish Green manifesto will, as expected, confirm the position that the party has stated previously on the monarchy and the constitution.
The party supports a written constitution and an independent Scottish Republic with an elected head of state.
Mr Harvie will tell a campaign event in Edinburgh on Wednesday that he wants Scotland to have the powers to hold a referendum on our constitutional future and establish a modern democratic republic.
Mr Harvie said: “The monarchy is a badly outdated and fundamentally undemocratic institution. It represents a different era and feels increasingly irrelevant and ridiculous in the 21st century.
“Yet, in a matter of weeks the full pomp and pageantry of Monarchy will be on display when the King does the state opening for a new government.
“We should be able to challenge power and elect or remove our head of state through the ballot box, like most countries do.
“We need a written constitution, drawn up by the people to entrench our rights and our democracy and to avoid the kind of power grabs and stunts that we have seen from Westminster.
“The Scottish Greens are the only party that is calling for an independent Scottish republic where power lies with the people rather than being handed down like a family heirloom.
“There are countries all across the Commonwealth who are asking questions about the way they are ruled and who are reconsidering their relationship with Monarchy. Scotland must have the chance to do the same.”
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