Readers who do not subscribe to New York Times Co.'s namesake newspaper will be able to read 20 articles per month on the website for free, but will have to pay to read more, the company said last week.

Subscribers to the print edition will have full, free access to the website, NYTimes.com.

The newspaper has launched the pay model in Canada and plans to roll it out in the United States and globally on March 28.

The pay model is a big test for large-circulation general interest newspapers, which have struggled to retain readers and advertisers as more and more people get their news from the Internet.

The scheme is being closely monitored by other news organizations weighing similar plans.

The Times' new pay model allows casual readers to access the New York Times, unlike some other pay strategies such as News Corp.'s experiment with the Times of London. The British paper bars anyone who does not pay from reading its website, which has resulted in a 90 percent plunge in visitors.

About 31.4 million individuals visited NYTimes.com in February, according to online research measurement firm comScore.

"We need to make sure that part of our business continues to grow," said Martin Nisenholtz, senior vice president of digital operations at the company. "The way we think we can do that is taking this metered approach charging the folks who are drinking deeply."

This is the second attempt by the New York Times, one of the world's most prestigious papers, to charge for digital news in hopes of diversifying its revenue stream.

It will charge US$15 per month, or 4 weeks, for unlimited access to NYTimes.com and a smartphone application; US$20 per month for online access and an Apple Inc. iPad app; and US$35 per month for online, smartphone and an iPad app.

Readers who come to Times articles from other sources such as blogs and social media sites including Facebook will be able to access content even if they hit the limit. However, the Times is limiting the amount of free articles on Google to five a day.

"This marks a significant transition for The Times, an important milestone in our 159-year history of evolution and reinvention," New York Times Chairman and Publisher Arthur Sulzberger Jr. said in a statement.

It remains to be seen whether people will pay for digital news. Of the three dozen newspapers that have moved to some sort of online pay model, only 1 percent of readers have opted to pay, according to a recent study by the Pew Research Center's Project for Excellence in Journalism.