About 26 people fell ill on a Qantas flight from Chile to Australia. The passengers were treated and are now being quarantined at the Sydney airport.

Qantas said in a statement that the passengers contracted a type of gastro intestinal illness. The airline said that the patients were unwell before they boarded the flight from Santiago and the "symptoms became evident during the flight."

There were more than 300 people on the flight that departed from Santiago sometime after midnight (AEST) on Thursday, reported sbs.com. As a precautionary measure, Qantas has asked the other passengers to monitor their health over the next two days and report if they fall ill.

Six NSW Ambulance crews were on standby to assist the patients at the Sydney airport. According to The New South Wales state Health Ministry the cause of illness was norovirus infection, a common illness in Australia and in other parts of the world.

"Ambulance will assess the sick passengers, and if well enough to leave they can be cohorted through the airport with minimal exposure to other passengers," a Spokesperson from the Ministry of Health said, according to news.com.au.

"NSW Health has provided Qantas with a letter and factsheet about viral gastro to distribute to all departing passengers, as well as advice for cleaning and cabin staff, the spokesperson added.

In 2012, about 400 people aboard two cruises fell ill due to the norovirus infection. The virus is contagious and can affect anyone, according to CDC. It spreads via contaminated food, drink and surfaces. Common symptoms include diarrhea, stomach ache, nausea and vomiting.