Police have reversed the decision to ban a march near the G8 summit venue at Gleneagles where world leaders have begun to gather.
Police try to remove protesters from the M9 at Stirling
Senior officers had expressed fears about more violence after trouble broke out in central Scotland overnight.
They agreed to let protesters on buses proceed to Auchterarder, where the march set out at 1430 BST.
About 60 people were arrested in and around Stirling after cars and property were damaged and roads blocked.
Protesters were due to march through Auchterarder to within 500m of the steel fence which rings the five-star Gleneagles hotel where the summit takes place between Wednesday and Friday.
Many people on buses from across Scotland were heading for the village when the police said the march should not go ahead. The decision was reversed after a meeting with the organisers, G8 Alternatives.
It was scheduled to set off at 1300 BST but was delayed to allow the buses to arrive in Auchterarder. BBC correspondent Mark Simpson, who is in the village, said the atmosphere was "calm and good-natured".
Tayside Police assistant chief constable Willie Bald said: "We are extremely disappointed that due to the actions of people determined to cause serious disruption the march as originally planned and agreed with G8 Alternatives could not go ahead.
"Public safety has always been our priority and anyone who watched the television pictures of criminal and violent activities in Stirling this morning would understand why we had to proceed cautiously to ensure this march could go ahead safely."
The M9, the main route from Edinburgh to Gleneagles, remains blocked at Stirling.
Protests are continuing around Stirling and in parts of Perthshire as activists attempt to carry out their objective of closing roads and rail links serving the summit venue.
Chief constable Peter Wilson, who is in charge of the G8 police co-ordination centre, said the time for playing "softball" with those intent on causing trouble was now over.
Protesters involved in the trouble overnight had shown no interest in "low-level consensual policing" and he anticipated more arrests.
World leaders arrived at Prestwick Airport in Ayrshire before transferring to Gleneagles.
A major security operation was in place as the international delegates flew in to be greeted by Scottish First Minister Jack McConnell, who condemned the violence.
Youngsters from Auchterarder Community School were to have joined other children welcoming the arriving world leaders at Prestwick but their trip had to be cancelled because of the traffic disruption caused by protesters blockading roads.
Prime Minister Tony Blair arrived at Edinburgh Airport from Singapore just before 0700 BST and boarded a helicopter to head to Gleneagles.
More than 150 aircraft will arrive at and depart from Glasgow Prestwick during the day, including G8 aircraft and departing helicopters.
With the summit set to begin, the British Government faced accusations it was using the issue of aid for Africa to try to improve its international reputation after the "disaster" of the wars in Afghanistan and Iraq.
WHAT IS THE G8?
Group of eight major industrialised states, inc Russia
Canada, France, Germany, Italy, Japan, Russia, UK, US
Originally set up to discuss trade and economic issues
Now leaders discuss global issues of the day
2005 Summit agenda
In a Commons debate on Tuesday, MP George Galloway told MPs the whole G8 system needed to be overturned.
But Foreign and Commonwealth Office minister Kim Howells accused the Respect MP of "self-righteous paranoia", saying the G8 could make a real difference to Africa.
Meanwhile, thousands of people are expected to flock to Edinburgh for the Live 8 - The Final Push concert at Murrayfield stadium.
The event, which features James Brown, Travis, Snow Patrol, George Clooney, Bono and The Proclaimers, is the culmination of Bob Geldof's Long Walk to Justice campaign.
Geldof, who arrived by train in Scotland on Tuesday, has called for a million people to gather in the city on Wednesday to put pressure on G8 leaders to act on poverty.
But Lothian and Borders Police have said there are no planned marches or rallies in the capital and urged the public not to turn up unless they had one of the 50,000 tickets for the Murrayfield concert.
As part of The Long Walk To Justice campaign, there are plans for a massive collection of hundreds of thousands of photographs - The G8 Gallery - posted along two miles of railings in Princes Street.