Ontario's immigration website has experienced a tenfold increase in visits since the province reopened its popular Provincial Nominee Program on Tuesday.

Applicants complained that ontarioimmigration.ca crashed almost immediately as they scrambled to compete for one of the 6,000 spots open for 2017. Once the annual quota is met, the system automatically stops taking applications.

Even those who were lucky enough to get a confirmation number and were invited to complete the online application in seven days said they have been unable to log onto the website.

According to the Ontario Ministry of Citizenship and Immigration, its website has received more than 117,000 visits since Tuesday when the so-called PNP program started accepting applications. The program was suspended last year while it was under review.

"We are aware that some individuals have been having difficulty with the online application system. This program is hugely popular and under significant demand, which we are doing our best to meet," said ministry spokesperson Laura Sylvis.

The PNP allows provinces to select and recommend immigration candidates to the federal Immigration Department. In Ontario, the capacity has doubled from 2,500 in 2014 to 6,000 this year.

There are three streams under the provincial program: one for master's graduates, another for PhD graduates, as well as a third stream for those whose skills are in demand in Ontario. The graduate streams are particularly popular because they do not require Canadian work experience.

Bowen Yang, an international graduate from Queen's University's biomedical engineering master's program, said it took him 18 hours in front of his computer to get onto the ministry's website Wednesday and receive his confirmation number.

However, since then, he has been unsuccessful in getting back into his preliminary profile to complete the full application.

"I kept refreshing my computer. Every time it just crashed again. I know of people who spent three days without sleep just to log on," said the 27-year-old, who came to study in Canada from China in 2012. "Everyone is frustrated. I can't log back on to complete my application. I am running out of time."

Sylvis said the international master's stream met the quota in less than 48 hours and the PhD program was also full by Friday.

"Both streams are now being paused to process these applications, but will reopen within the next three months," she explained. "We have asked prospective applicants to check our updates webpage on May 1."

She said the ministry is working closely with its IT partners to address the technical issues and will continue to communicate with applicants through the program website and social media.