Serious rioting has erupted in Belfast injuring 22 officers, police said, as tension mounted before the culmination of Northern Ireland's main Protestant marching season.

Police used water cannon and fired 51 plastic bullets to try to disperse around 200 Catholic rioters in the Broadway area of mainly Catholic west Belfast late Monday.

Rioters responded with a hail of bricks and more than 40 petrol bombs.

A bus was hijacked and driven at a police cordon separating Catholic Nationalists from Protestant Loyalists around 200 metres away, but crashed before reaching the cordon.

Four of the 22 wounded officers were taken to hospital. Their injuries were not life-threatening, the Police Service of Northern Ireland (PSNI) said.

PSNI assistant chief constable Alistair Finlay said: "No one wants to see disorder return to any part of Northern Ireland. Such violence damages local infrastructure, it sets back relationships and leaves wounds which take time to heal.

"We know it is a difficult time for some communities and we encourage everyone with influence to keep talking, making their peaceful voices heard and working towards meaningful solutions and a peaceful summer."

The marching season comes to a climax later on Tuesday and marks the Battle of the Boyne in 1690 when king William III, a Protestant, defeated the Catholic king James II, whom William had unseated two years earlier.

Trouble first flared late on Monday when Protestants began lighting bonfires, the signal for the start of the Twelfth, a day of celebrations during which tens of thousands of "Orange Order" men are expected to march.

"There is no other single event that can produce crowds like the Twelfth. It is such a special day of religion, culture, music and pageantry," said Orange Order grand master Edward Stevenson.

Northern Ireland saw some of its worst sectarian violence in years two weeks ago, focused on a Catholic enclave in east Belfast.

The 1998 "Good Friday" peace accords largely ended the cycle of sectarian bombings and shootings in the province, part of the United Kingdom, and paved the way for a devolved, power-sharing Northern Irish Assembly.

Around 3,500 people were killed in decades of unrest pitting Protestant Loyalists who want the province to remain part of the United Kingdom against Catholic Republicans who favour joining the Irish Republic.

- AFP