"The precise answer is, I don't know," the smiling Buddhist monk said when the question was put to him by a reporter.

His Holiness the Dalai Lama, on the last day of his Australian tour, nonetheless captivated about 30,000 people who stood listening to him talk for more than an hour on "The Power of Compassion" in the rain-sodden grounds of The Domain.

Buddhist monks, Christians, atheists, supporters of Tibet and curious young people were among those who ignored storm warnings and braved strong winds and intermittent drizzle to see the charismatic spiritual leader.

For Bjoern and Agnes Schliebitz, who came from North Narrabeen with their daughter Cille, 4, it was a long-awaited moment.

"I'm not a Buddhist, but he's a man of peace and truth," Mrs Schliebitz said.

The Dalai Lama was introduced by Sydney Swans co-captain and practising Buddhist Brett Kirk, who handed over a gift of a signed Swans T-shirt.