At least 5,000 people are expected to attend an anti-G8 march in Northern Ireland on the eve of a meeting of world leaders in the region.

Environmentalists, trade unionists and other civil society activists will parade through Belfast city centre at lunchtime for what they bill as a march and festival for a fairer world.

US President Barack Obama is among the premiers arriving at the Lough Erne golf resort in Fermanagh for the two-day meeting starting on Monday.

A separate concert for the IF anti-food poverty campaign, spearheaded by charities working in the developing world, will be held in the city's Botanic Gardens in the afternoon with acts including indie rockers Two Door Cinema Club. The concert has been sold out, with around 8,000 people due to attend, organisers said.

Campaigners behind the city centre march said: "We believe that achieving social, economic and environmental justice must be central to political decision-making."

Environmentalists will carry a 100m-long "polluted" river during today's demonstration. Friends of the Earth will bear props representing the alleged damage done by a form of natural gas extraction known as fracking. The pressure group wants to stop potential drilling in rocks in Co Fermanagh near where the conference of world leaders is being held.

The Irish Congress of Trade Unions has helped organise the parade and Amnesty International is also supporting it.