A protest is being planned against the monarchy during King Charles III's first visit to Wales since ascending the throne.
The organisers said the silent demonstration will begin from 1pm at Cardiff Castle on Friday.
The castle is one of three locations Charles will visit during his day-long tour of the capital, and where he will meet charitable organisations and faith leaders after having a private audience with First Minister Mark Drakeford.
Those attending the rally are expected to stand and hold signs with slogans such as "Why a Monarchy?" and "Real democracy now".
Campaigners say they want the Welsh public to consider whether a future without the monarchy is possible.
They have called on the Welsh government and Cardiff Council to ask South Wales Police to respect their democratic right to protest, following the arrests and threats of action against people holding signs saying "Not my King" in other cities.
Activist and former Wales MP Bethan Sayed said: "As soon as King Charles III decided to announce that Prince William should become Prince of Wales, so soon after the death of the Queen, many of us felt compelled to respond.
"We must discuss the future of Wales, and what we want that to look like.
"People tell us that now is not the time to discuss this issue, however, when the monarchy passes from the incumbent to a new King, now is exactly the time to discuss this matter.
"It is about fairness, equality, and the Wales we want to shape for future generations."
Speaking to PA, Sayed added: "It is still a difficult time and we totally appreciate that. We all have family who've passed away.
"So we have no intention of causing issues but we want our rights to hold and express a different view to be respected.
"Because that is entirely legitimate if we actually call ourselves a democracy."
A number of groups are joining to lead the protest under the banner Real Democracy Now, including trade unions, Welsh independence organisations and republicans.
However, Sayed said anyone was invited to join including those wanting to protest against imperialism.
Leader of pro-independence party Plaid Cymru, Adam Price, has said a debate on the subject should be held "in due course".
The party believes that in an independent Wales, people should have the right to vote on whether or not to keep a member of the royal family as head of state.