Occurrences of worldwide flooding has cornered the bulk of global insurance claims for the first half or six months of the year 2013, according to preliminary data released by Switzerland-based reinsurance giant Swiss Re on Wednesday.

"The global insurance industry covered $20 billion of the total losses, of which $17 billion were caused by natural catastrophes, in large part due to widespread flood events," Kurt Karl, Swiss Re chief economist, said in a statement.

Massive June floods in Central and Eastern Europe alone have cost insurers $4 billion, while floods in Alberta, Canada, amounted to $2 billion.

Other flooding insurance claims were likewise reported India, Australia, Southern Africa, Indonesia and Argentina.

Swiss Re said that based on statistics on insured flood losses which reached $8 billion in the first six months, the year 2013 has been dubbed as the second most expensive year in terms of flood claims, next to the 2011 Thai floods which hit $16 billion.

Although disaster costs compared from a year ago declined by 16 per cent, Swiss Re said there still remains six more months in 2013.

Though 2013 has so far been a below-average loss year, the severity of the ongoing North Atlantic hurricane season, and other disasters such as winter storms in Europe, could still increase insured losses for 2013 substantially," Mr Karl said.

A total of 7,000 lives were lost in the first half of 2013 from both natural catastrophes and man-made disasters.