Adisa said she was keen to call the gathering an advocacy network meeting rather than a protest.
"Kate and William are beneficiaries, so they are, in fact, complicit because they are positioned to benefit specifically from our ancestors, and we're not benefitting from our ancestors.
"The luxury and the lifestyle that they have had and that they continue to have, traipsing all over the world for free with no expense, that is a result of my great, great grandmother and grandfather, their blood and tears and sweat."
Her comments come after an open letter from Jamaican politicians, doctors, businesspeople and musicians was published calling for reparations.
Adisa argued that the British monarchy should offer "economic social reparation", like "building us proper hospitals, providing and making sure that our children are educated through college level, and making sure land is equally distributed".
She added that an apology would be the "first step towards healing and reconciliation".
"You know, we don't have anything personally against Kate and Prince William, and even the Queen, for that matter.
"But we're simply saying you've done wrong, and it is way past time that you admit that you've done wrong and when you do, redressing it.
"The fact that our government is spending money to help provide security and finance for the duke and duchess, who are wealthy, is outrageous, it's criminal.
"Because the Caribbean is fed up, the same thing happened in Belize. We're just saying enough is enough, we've been quiet, we have been nice."
The protest comes amid recent calls from politicians for Jamaica to drop the Queen as its head of state and become a republic.
Last year Barbados became a republic and started a new constitutional chapter.
The Duke and Duchess's tour in the Caribbean hasn't quite gone as planned.
They were also forced to cancel a visit to a farm in Belize after protests from its community, citing a range of issues including objections to the royals' helicopter landing site.
