Australian Tiarna Thompson had her dream Bali wedding all set, but there was one thing she did not count on: a volcano threatening its first major eruption in half a century.

The 24-year-old and her fiance Justin saw their plans go up in smoke when Mount Agung rumbled to life, spewing ash and fumes that forced hundreds of flights to and from the island to be cancelled.

"It's funny how a volcano can just turn our plans and our whole lives sort of upside down, just like that," said Thompson from her home near Brisbane.

The couple, who had planned to get hitched in the picturesque tropical paradise this week have hurriedly switched their nuptials to Thailand.