AFP/ Kathmandu

Nepal Sunday adopted a new constitution aimed at bolstering its transformation to a peaceful democracy after decades of autocratic rule and a long civil war, even as protests raged over its terms.

The charter, the first to be drawn up by elected representatives, had been voted into law Wednesday after the main political parties -- spurred by a deadly earthquake to shelve differences -- agreed on a new federal structure.

Firecrackers went off in celebration in Kathmandu as President Ram Baran Yadav announced the adoption of the long-delayed constitution at a ceremony in parliament.

"I congratulate all Nepali brothers and sisters on this historic moment, the announcement of Nepal's constitution from the Constituent Assembly by the representatives of the people for democratic rights, economic prosperity and national unity," he said.

"The democratic revolution of Nepal's people which began nearly seven decades ago and the people's wish for long-term peace has become a reality today."

The new constitution is the final stage in a peace process that began when Maoist fighters laid down their arms in 2006 after a decade-long insurgency aimed at abolishing an autocratic monarchy and creating a more equal society.

But its adoption follows weeks of clashes between police and protesters that have left more than 40 people dead, among them two children and a police officer lynched as he was driven to hospital in an ambulance.

One protester was killed on Sunday when police fired into a crowd which had defied a curfew in the southern district of Parsa to demonstrate against plans to divide the world's youngest republic into seven federal provinces.

The move to create a new federal structure that will devolve power from the centre has widespread support, but critics say the planned internal borders will leave some historically marginalised groups under-represented in parliament.

They include the Madhesi and Tharu ethnic minorities who mainly inhabit Nepal's southern plains, along the border with India.

Neighbouring India has expressed concern at the violence, which has seen some parts of southern Nepal shut down for weeks.

- Deadly quake -

Work on the bill began in 2008 after the Maoists won parliamentary elections and abolished the monarchy.

It was initially supposed to finish by 2010, but the Maoists were unable to secure enough support for the two-thirds majority needed to push it through parliament.

The three biggest forces in parliament -- the Nepali Congress, UML and Maoist parties -- finally reached agreement in June, spurred by a 7.8-magnitude earthquake two months earlier that killed nearly 8,900 people and destroyed around half a million homes.

But there has been strong opposition from some quarters, including Hindu groups who do not believe Nepal should be a secular state.

Rights groups say it discriminates against women by making it more difficult for them to pass on citizenship to their children than it is for men.

Hundreds had gathered Sunday outside parliament in Kathmandu, which was decked out in balloons and Nepali flags.

The mood on the capital was broadly celebratory although there were some protests early Sunday by political groups who oppose the bill.

They include a breakaway faction of the Maoist party whose spokesman Khadga Bahadur Biswakarma said the new charter was "against the spirit of the war we fought and the people's revolution".

Critics say the new charter does too little to empower minorities, and many took to Twitter to voice their disapproval under the hashtag #notmyconstitution.

Bhimarjun Acharya, a constitutional lawyer, said the bill included provisions for improving the involvement of low-caste groups, women and minorities in national politics, although he said some of these were not clear-cut and success would depend on how they were implemented.

Sentiment was mixed on the streets of Kathmandu, with many residents saying they hoped to see an end to the protests and political instability that have held back the impoverished country.

The new constitution will trigger the resignations of both the government and the president, although the timing of those changes is unclear.

"We have waited for this for so long. I am happy today, but there is also a sense of sadness because we have seen so much violence in the last weeks," said finance worker Nabina Ranjit, 27.

"I wish everyone would be celebrating today, but unfortunately, the leaders have failed to address grievances of all Nepalis."