Saudi Arabia's new king has promised to continue to the policies of his predecessors.

King Salman bin Abdul-Aziz Al Saud made the comments in a televised speech today.

King Salman said: "We will continue adhering to the correct policies which Saudi Arabia has followed since its establishment."

King Abdullah died today at the age of 90 after nearly two decades in power.

King Salman immediately took power in the oil-rich Sunni kingdom.

Salman also made an oblique reference to the chaos gripping the greater Middle East as the extremist Islamic State group now holds a third of both Iraq and Syria.

"The Arab and the Islamic nations are in dire need for solidarity and cohesion," the king said on the state-run Saudi 2 station.

Salman, 79, had increasingly taken on the duties of the king over the past year as his ailing predecessor and half brother, Abdullah, became more incapacitated.

Salman had served as defence minister since 2011.

That made him the head of the military as Saudi Arabia joined the United States and other Arab countries in carrying out air strikes in Syria in 2014 against the Islamic State group, the Sunni militant group that the kingdom began to see as a threat to its own stability.

He takes the helm at a time when the ultraconservative Muslim kingdom and oil powerhouse is trying to navigate social pressures from a burgeoning youth population - over half the population of 20 million is under 25 - seeking jobs and increasingly testing boundaries of speech on the Internet, where criticism of the royal family is rife.

Salman's health has been a question of concern.

He suffered at least one stroke that has left him with limited movement on his left arm.