Six Dr Seuss books will no longer be published because they "portray people in ways that are hurtful and wrong," the business that preserves the author's legacy said, CNN reports.

The titles are:

"And to Think That I Saw It on Mulberry Street"

"If I Ran the Zoo"

"McElligot's Pool"

"On Beyond Zebra!"

"Scrambled Eggs Super!"

"The Cat's Quizzer"

In a statement, Dr. Seuss Enterprises said it made the decision after consulting educators and reviewing its catalog.

"Ceasing sales of these books is only part of our commitment and our broader plan to ensure Dr. Seuss Enterprises's catalog represents and supports all communities and families," it said.

The announcement was made Tuesday, the birthday of the famed children's book author.

Seuss, born Theodor Seuss Geisel, is one of the best-known authors in the world, the man behind beloved classics like "The Cat in the Hat," "Green Eggs and Ham" and "How the Grinch Stole Christmas," among others. Over 650 million copies of his books have been sold worldwide, the Washington Post reported in 2015.

The books also been made into movies, including 2000's How The Grinch Stole Christmas starring Jim Carrey and 2012's animated 3D film The Lorax, the BBC said.

Despite the books' popularity there has been disquiet expressed over the way they portrayed non-white characters.

For example, In And To Think That I Saw It On Mulberry Street, a character described as Chinese has two lines for eyes, carries chopsticks and a bowl of rice, and wears traditional Japanese-style shoes.

Another title, If I Ran the Zoo, depicts two men from Africa as shirtless, shoeless and wearing grass skirts as they carry an exotic animal.

The National Education Association in the US, which founded Read Across America Day in 1998, has in recent years put less emphasis on Dr Seuss's works, instead suggesting a more diverse reading list for children.

Some school districts in the US have also moved away from recommending the author. The Daily Wire reported last week that Loudoun County Public Schools in Virginia had already told its teachers to "avoid connecting Read Across America Day with Dr Seuss".

"Realising that many schools continue to celebrate Read Across America Day in partial recognition of Dr Seuss' birthday, it is important for us to be cognizant of research that may challenge our practice in this regard," Loudoun County Schools said.

"As we become more culturally responsive and racially conscious, all building leaders should know that in recent years there has been research revealing radical undertones in the books written and the illustrations drawn by Dr Seuss."

The Cat In The Hat, one of Dr Seuss's most popular books, has also received criticism but will continue to be published for now.

Other popular children's books have been criticised in recent years for alleged racism.

Babar's Travels was removed from the shelves of libraries in East Sussex in the UK after complaints of racism from words used such as "savage cannibals".

Similar complaints have led to some of Herge's Tintin adventures being removed from libraries, or moved to the adult section.

And criticism over Laura Ingalls Wilder's portrayal of Native Americans in her Little House On the Prairie novels led to the removal of her name from a lifetime achievement award handed out annually by the American Library Association, the BBC reported.

Six 'hurtful' Dr Seuss books pulled from sale