A massive increase in Chinese nationals arriving on temporary migrant visas, in particular international students, are driving soaring refugee claims, experts say.

Months after Chinese regulators said they would step up scrutiny of tech companies with shares traded on foreign exchanges, Didi Global announces it will be swapping New York for Hong Kong.

The Australian share market is trading fairly flat, as a rebound in tech stocks is not enough to lift the major indices.

Emergency crews are still working to find 300 workers who could be trapped in sludge after a dam burst at a Brazilian iron ore mine, killing dozens of people and inundating a nearby community with liquid waste.

By December, the New Zealand government is expected to make its final decision on how agricultural emissions will be priced, but farmers are already protesting the move.