The Dreamworld theme park tragedy on the Gold Coast in October hurt the bottom line of Mantra Group, with Australia's biggest listed hotel and resort operator, delivering full-year operating earnings at the bottom end of its market guidance.

Mantra reported underlying pre-tax earnings of $101.2 million, up 12.7 per cent on the same period last year, having forecast an earnings range of $101 million to $107 million in February.