Wealthy Qatar said on Monday it will purchase $500 million of government bonds in debt-ridden Lebanon a day after the country's emir visited Beirut to attend the Arab economic summit.

"The state of Qatar will buy Lebanese government bonds valued at 500 million US dollars," Foreign Minister Mohammed bin Abdulrahman Al-Thani said in a statement carried by the Qatar News Agency.

The purchase would "strengthen the Lebanese economy", and the decision was taken after a meeting on Monday between Qatar's Emir Sheikh Tamim bin Hamad Al-Thani and Lebanese President Michel Aoun, he said.

"We wish stability and prosperity for the Lebanese republic and the Lebanese people, and that the Lebanese economy will recover."

The move comes amid huge financial strains for the Lebanese government.

Lebanon's finance minister spooked markets earlier this month with comments about the country's public debt, thought to be among one of the worst in the world.

Lebanon's economy has looked on the brink of collapse for some time but a Paris conference dubbed CEDRE in April made aid pledges worth $11 billion.

But France last month warned that Beirut could lose those pledges if it continued to be without a government almost eight months after general elections because of political disputes.

The Qatari bond purchase may have wider political implications also.

Qatar is at the centre of a bitter dispute with Egypt and three neighbouring Gulf states including Saudi Arabia, traditionally a backer of Lebanon's prime minister-designate, Saad Hariri.

Since June 2017, Saudi Arabia, the United Arab Emirates, Bahrain and Egypt have cut almost all diplomatic and economic ties with Qatar, accusing it of supporting terrorism and seeking closer ties with Riyadh's regional rival, Iran.

Qatar says it neighbours are seeking regime change and denies the charges.