Former US President George W. Bush has led tributes to Dick Cheney, saying his death is a loss to the nation and a sorrow to his friends.

Cheney died from complications of pneumonia and cardiac and vascular disease on Monday night at the age of 84, his family said in a statement.

He became one of the most powerful US vice-presidents in history under Bush, and leaves behind a controversial legacy as a key architect of the war on terror, and an early advocate of the 2003 invasion of Iraq.

History will remember him as among the finest public servants of his generation, Bush said in a statement.

Cheney was a patriot who brought integrity, high intelligence, and seriousness of purpose to every position he held, Bush added. I counted on him for his honest, forthright counsel, and he never failed to give his best. He held to his convictions and prioritized the freedom and security of the American people.

Condoleezza Rice, who served as Secretary of State alongside Cheney in the Bush administration, said she admired him for his integrity and his love of our country. He was an inspiring presence and mentor who taught me a great deal about public service, she wrote.

Recognized as a controversial figure, Cheney's significance intensified in the aftermath of the 9/11 attacks, where he played a pivotal role in shaping US foreign policy. His ardent support for military action in Iraq has defined his legacy, leading many to reflect on the chaos and consequences that followed.

Leaders from both parties have recognized Cheney's complex legacy, with acknowledgments of his impact juxtaposed against criticisms from various fronts. His family described him as a great and good man who taught his children and grandchildren to love our country.

Following his death, flags were lowered to half-staff at the White House in a symbolic act of respect. Cheney's intricate history in public service continues to resonate through political discussions, emphasizing a career marked by devotion amid divisive perspectives.