The 66-year-old, elected to her country's parliament in April after two decades under house arrest, listened attentively to the parliamentary debate in the capital Bern. Activists from Amnesty International greeted her.

Suu Kyi, making her first trip to Europe in nearly a quarter of a century, was taken ill on Thursday evening, vomiting during a news conference in Bern and earlier on the train from Geneva.

"Having stayed in one place for so long, I found the plane journey out to the West extremely exhausting and a little bit disorienting because I couldn't adjust to the new time as quickly as I might have 24 years ago," she said on Thursday.

"I'm so sorry," she told reporters as she hastily left the room. She recovered to attend a cocktail party in her honour, but the official Swiss dinner was cancelled.

Her doctor, Pyone Moe Ei, expressed concern for Suu Kyi's health, telling Associated Press that her "lack of rest and her extremely tight schedule are very worrisome". Moe Ei said that Suu Kyi has low blood pressure and gets motion sickness easily but has no major health problems.

In a speech on Thursday to the International Labour Organisation, she urged foreign governments not to let their companies form joint ventures with Myanmar's state-owned oil and gas company until it improved its business practices.

For two decades, Suu Kyi passed up opportunities to leave Myanmar in fear the ruling generals would block her return.

Asked on Thursday whether she hoped to follow in the footsteps of her late father Aung San, who led Myanmar's campaign for independence from British rule, she replied:

"It's not for me to say whether or not I am going to be the leader of my country. It is for my people to decide. They were the ones who decided that my father should be their leader. If you believe in democracy, you don't decide who is going to be the leader, you let the people make the decision."

The Oxford-educated Suu Kyi was due to fly later on Friday from Zurich to Oslo, where she will receive her Nobel prize. Other stops during her 17-day tour include Britain, France and Ireland.