Mother-of-three Alice Tocher (31) went missing after dropping her daughter off in St Kilda on Thursday. Her passport had been found in Brisbane.
Peter Tocher, who lives in Melbourne, told the Otago Daily Times this morning he was going to Brisbane to join the search.
"It's a bit like looking for a needle in a haystack. We don't know what to do, that's the problem.''
Last night, he said Air New Zealand confirmed that his daughter booked a ticket to Brisbane from Christchurch on Friday.
He believed she bought a "random ticket'' for the cheapest flight to Australia, either Brisbane or Sydney.
"Melbourne is a bit more expensive and she's thought, 'I just have to get away' and she's landed in Brisbane and doesn't know what to do.''
Brisbane police believed Ms Tocher was still in the city and would be "in a very distressed state'', Mr Tocher said.
Security guards had found her handbag near a museum in Brisbane yesterday afternoon with her passport and driver's licence inside.
"We just hope she has some cash in her pocket and that she hasn't been abducted and the handbag has been thrown away and the cash taken out of it.
"She is in a country now of 24 million people, where at least in New Zealand it was 4 million people and it was a bit smaller - we are beside ourselves.''
Brisbane police were reviewing CCTV footage and the results were expected soon.
The only people she knew in Australia were her parents in Melbourne, Mr Tocher said.
