The body of Romania's beloved former king Michael, who recently died in Switzerland aged 96, returned Wednesday to his home country where he will be laid to rest at a grand state funeral.

The remains of one of the last surviving World War II leaders arrived in Bucharest early Wednesday.

A solemn ceremony was held at the airport in the presence of the king's five daughters, Romanian officials and senior Orthodox prelates.

Covered in the regal coat of arms, the coffin was then taken to the castle north of Bucharest where he was born.

It was due to return to Bucharest by late Wednesday and be put on display in the Royal Palace ahead of Saturday's state funeral.

The king, who passed away on December 5 following a battle with leukaemia had largely withdrawn from public life after announcing his illness last March.

But he remained a revered monarch for many Romanians who will observe three days of mourning from December 14-16, with the national flag flown at half-staff.

His death prompted an outpouring of accolades from top officials, with Prime Minister Mihai Tudose calling the former king "a model of morality and dignity".

Michael, a descendant of the German Hohenzollern dynasty, ruled Romania twice, from 1927-1930 and then from 1940-1947, when he led a coup that ousted marshal Ion Antonescu and saw Bucharest join the allied forces against Hitler.

But the postwar communist government ended the monarchy in the Balkan country and Michael was forced to abdicate and go into exile in December 1947.

Stripped of his citizenship, he eventually settled in Switzerland, where he earned a modest living as an aircraft mechanic and farmer.

He finally returned to Romania in 2002.