BILLIONAIRE DAVID KOCH, a major donor to the Republican party, has died at the age of 79.

Koch Industries, the Kansas-based energy and chemical company which he co-owned with his brother Charles, reported his death today.

“It is with a heavy heart that I announce the passing of my brother David,” Charles said in a statement, according to US television network NBC.

“Anyone who worked with David surely experienced his giant personality and passion for life.”

In a tribute to him, Koch Industries said he contributed more than $1.3 billion to cancer research, medical centres and arts and cultural centres during his life.

According to Forbes, he was the 11th richest person in the world – tied with his brother- at the time of his death.

He previously survived a plane crash and was given five years to live when he was diagnosed with terminal prostate cancer 27 years ago. 

The two brothers had a significant influence on the conservative movement in the US, and David ran for vice-president as a Libertarian candidate in 1980.

They founded Americans for Prosperity, a charity which has supported conservative presidential candidates who adhere to the ideals of a free-market and small government.

However, the group has frequently clashed with current President Donald Trump, particularly over his trade tariff policy.