Endless rows of mud-caked vehicles damaged by deadly floods last month sit abandoned in a parking lot in Zhengzhou, an unwitting memorial to the power of the disaster that hit Henan province.

The region is rebuilding after the deadliest floods in a decade wreaked havoc across the province mid-July, killing over 300 people and damaging thousands of cars and buildings.

"We were forced to abandon our vehicles and leave when the waters rose," a Zhengzhou resident surnamed Wang said.

At least 238,000 damaged vehicles have been sent to 'graveyards' like the one in the outskirts of Zhengzhou, head of Henan's insurance regulator Ma Chao told state broadcaster CCTV on Tuesday.

Record downpours dumped a year's worth of rain on Zhengzhou -- the capital of Henan province and the epicentre of the flooding -- in just three days, with over 290 people killed. 

Dozens of people died while trapped in flooded subway carriages, underground car parks and tunnels.

The floods also triggered record insurance claims worth $1.7 billion after thousands of cars and buildings were damaged, insurer Goldman Sachs said in a July report.

The local government last week said economic losses due to the floods have ballooned to over $20.65 billion and promised swift compensation.