Ness offered to match the first £10,000 in donations, an offer that was itself matched by fellow authors John Green, Derek Landy and Jojo Moyes.
Other writers rallied to the cause, exhorting their readers to donate.
"What started out as a small thing has exploded," wrote Ness on Friday on his official fundraising page.
With gift aid and other pledges included, the award-winning author has estimated that nearly £200,000 had been raised for the Save the Children charity.
In his initial post, Ness - whose works include A Monster Calls and the Chaos Walking trilogy - said he was "tired of just tweeting [his] despair about the current refugee crisis".
Initially hoping to raise £20,000, he said he had been "astonished at how people have responded".
"I think, by pure accident, I happened to express my frustration at the right moment," the author told The Bookseller.
Calls for the UK to take in more refugees have intensified after the publication of a picture of the body of a drowned three-year-old Syrian boy, Alan Kurdi, washed up a Turkish beach.
Prime Minister David Cameron is expected to announce plans later to increase the number of refugees being allowed into the UK.
A campaign set up by children's author Patrick Ness to raise funds for Syrian refugees has raised more than £150,000 in 24 hours.