It's expected to climb and has already reached number one in the "Fiction about Value and Virtues for Children" subcategory on the website.
People have already snapped up copies online and shared their thoughts in the reviews section about the book, which appears to have split opinion among readers.
"The average child won't appreciate or understand this. It would be a better gift for someone who's a father rather than gifting this to a child. It's also very expensive considering the value for money derived. It's incredibly short."
Others defended the writing as "clearly meant more for a father or parent to read and give them a smile" despite it being sold as a book for kids.
A positive review titled "Beautiful keepsake" read: "The poem throughout is lovely Don’t really understand the negative reviews, it’s a beautiful book and clearly meant more for a Father or parent to read and give them a smile. My children loved looking at the pictures and pointing out ‘daddy’, but it made my husband tear up".
One reader also praised the poem for showing "diversity" by representing a range of different families in its "gorgeous" illustrations.
Meghan Markle's children's book has jumped to the top five on Amazon bestsellers within hours as reviews pour in branding it everything from "beautiful keepsake" to "semi-literate vanity project".
"The Bench," which has an average rating of four stars online, was inspired by a poem the Duchess of Sussex wrote about Prince Harry's first Father's Day.
It promises to explore "the special relationship between father and son, as seen through a mother's eyes" and was released on Tuesday.