"Brazil is an extremely important market," Amazon representative Alex Szapiro told AFP.
"There is an expanding middle class and we see a great opportunity for growth."
Amazon got a foothold in this South American giant of 194 million people only in December, launching its basic Kindle reader, which competes with Japanese maker Rakuten's Kobo model and with those of US electronics giant Apple among others.
With the introduction of the more advanced Paperwhite, Szapiro said his company has "high expectations," although he would not give figures or details of future plans.
"It is important that Brazilians see this new device as an iconic e-reader," he noted.
Asked whether Amazon would broaden its product line in Brazil or organize similar product launches elsewhere in Latin America, Szapiro stressed: "We are just at the beginning, there is much that could occur."
The Paperwhite entry is part of an aggressive blitz by Amazon offering a catalog of 1.6 million books, with more than 16,000 Portuguese-language titles and 2,500 free books.
The market for digital books in Brazil "is growing and generates a lot of movements among publishers," said Karine Pansa, president of the Brazilian Book Chamber.
"In the future, it will be profitable, but the business took off late. It took the arrival of Amazon for the others to react."
Leading bookstore chain Livraria Cultura launched the rival Kobo e-reader in December.
Others sell digital titles incompatible with the Amazon Kindle, but that can be read on Apple tablets.
The renowned Sao Paulo-based publishing house Companhia das Letras signed a deal late last year to sell Amazon digital books.
As in much of Latin America, book reading is not very popular in Brazil but the country has one of the highest rates of Internet usage.
According to pollster IBOPE, nearly 95 million Brazilians have access to the Web from their homes, schools, workplaces or cybercafes.
"Brazil is a country very receptive to technology, and this helps e-commerce," said Nelson Wortsman, head of infrastructure and digital affairs at information technology and communications association BRASSCOM.
"If a company of Amazon's size takes the trouble to come here, it is because it sees a lot of potential."
E-commerce revenue is also soaring, grossing 22.5 billion reais ($11.5 billion) in 2012, up 20 percent over the previous year.