Nepal's former king Gyanendra has said he is "troubled and anguished" by the state of his country, breaking his long silence in a message released to coincide with his 63rd birthday.

A year after stepping down from the throne at the request of the Maoist-led government, Gyanendra said he had agreed to become a commoner in the hope that "peace and the law and order situation would improve."

But he said there had been "no improvement in the lot of my beloved fellow citizens, my brothers and sisters."

"I am very perturbed, very troubled and very anguished," he said.

Gyanendra stepped down last year after Nepal's Maoists, who fought a decade-long civil war with the army, won landmark polls and legislated to do away with the world's last Hindu monarchy.

But the country was plunged into fresh political chaos on May 4 this year when Maoist leader Pushpa Kamal Dahal resigned as prime minister after just eight months following a failed bid to sack the head of the army.

A new coalition government has since taken over, but the Maoists have boycotted parliament, preventing it from sitting, and their affiliates have held a series of at times violent street demonstrations.

Gyanendra, seen by supporters as an incarnation of a Hindu god, has kept a low profile since the abolition of his 240-year-old dynasty.

After leaving the sprawling royal palace in the heart of Kathmandu, he moved to a former hunting lodge on the capital's outskirts and has made only a handful of appearances at religious festivals and family celebrations.

In his birthday message, the former king also urged against the breaking up of the landlocked Himalayan nation, where various ethnic groups have been calling for greater autonomy in recent years.

The southern Terai region, which runs along the border with India, has been particularly badly effected, with regular blockades held by ethnic groups who say they have been neglected by successive Nepalese governments.

"My request to all is that never any consent be given to break the Nepalese garland of the Himalayas, the hills and the Terai, so meticulously woven by the common efforts of the Nepalese people and my ancestors, by either internal discord or external ill-feeling," said Gyanendra.