SYDNEY, April 1 — Whole herds of cattle have drowned in vast inland floods sweeping across the Australian outback, officials said today, as the muddy tide drenched an area the size of France.

Swollen rivers burst their banks after unusually heavy downpours last week over outback Queensland, an arid region home to some of the country’s largest cattle ranches.

Officials said more than 100,000 livestock — cattle, sheep, goats and horses — had been swept away, were missing, or had drowned.

“These are only early indications of the magnitude of this disaster and while these preliminary numbers are shocking, we are expecting them to continue to climb as flood waters recede,” said state agriculture minister Tony Perrett.