The Vienna leg of a tour by American mega-star Taylor Swift has been cancelled after Austria arrested an Islamic State sympathiser in connection with an attack plot.

Authorities had earlier confirmed the arrest of a 19-year-old sympathiser of the armed group for allegedly planning an attack in the Vienna region, warning he had a "focus" on Swift's three upcoming shows.

Barracuda Music said on Instagram that with the confirmation from government officials of a planned terrorist attack at Ernst Happel Stadium, they had no choice but to cancel the three scheduled shows for everyone's safety.

The organisers added that all ticket holders would receive refunds, as about 65,000 spectators were expected at each show scheduled for Thursday, Friday and Saturday.

Austria's top security chief Franz Ruf told a press conference that the man who had pledged his allegiance to IS "in recent weeks" was detained in Lower Austria about an hour from the capital.

Ruf said the chemical substances had been seized at the suspect's home, disclosing that the second person believed to have been in contact with the suspect was arrested in Vienna.

According to the initial investigation, both suspects radicalised themselves on the internet.

The Police department had promised to ramp up security measures, including deploying special units for the concerts, while having minimised any concrete danger.