The number of arrests linked to the summit topped 100 as officers rounded up demonstrators accused of smashing their way into the Royal Bank of Scotland.
More than 80 people were detained in two disused buildings within walking distance of the Bank of England.
Hundreds more marchers returned to the Bank today and were involved in a tense stand-off with police who shut adjoining streets.
But there was no repeat of the sporadic violence that marred largely peaceful protests yesterday by campaigners calling for action from world leaders.
And the only groups who gathered in any numbers near the summit venue in east London were Ethiopians protesting about divisions in their home country.
Scotland Yard made 22 further arrests today, including nine for violent disorder, four for possessing an offensive weapon and four for breach of the peace.
The Met said anyone detained at the two squats who was not "of interest" would be released.
Dozens of police and an armoured police van blocked Earl Street, near Liverpool Street station, where a disused office block was raided.
Witnesses said a large convoy of police vans arrived quietly in a back street before riot police smashed their way inside the three-storey red-brick building.
At least 70 people were led out and made to sit in the street outside as they were questioned and searched by officers.
In Rampart Street, Aldgate, where four arrests were made, occupants of the three-storey building complained about police tactics.
One said: "It was major league over the top. They think we are some sort of terrorist masterminds and we are being linked with violence.
"We are not hardened criminals - we are all educated, civil-minded people."
The officer in charge of policing the G20 protest, Commander Bob Broadhurst, said police were using video footage gathered yesterday to track down violent activists.
He said the "overall mood" of yesterday's demonstrations was good. But he added: "Unfortunately small groups of protesters intent on violence mixed with the crowds of lawful demonstrators.
"Some have been arrested already and officers will be looking to identify others through footage from evidence-gatherers."
Tonight officers corralled a group on to the pedestrianised area in front of the Bank.
As a helicopter hovered overhead, lines of police officers cleared milling protesters from surrounding streets.
There were minor skirmishes as other pockets of protesters were also kettled - a police tactic which involves holding them in small areas.
Once the streets at the busy junction were clear, traffic was allowed to continue flowing but exits to Bank Tube station were closed and those on foot were held back.
It was not clear who the group of protesters were but many of them were dressed in black and some carried Communist Party and socialist flags.
A large number of police vans lined nearby Cornhill and a squad of mounted police were on standby in a side street.
Police were taunted with chants of "shame on you" as they forcefully pushed protesters into groups and other officers photographed protesters.
Home Secretary Jacqui Smith made a visit to the police G20 nerve centre today.
A spokesman said: "The Home Secretary received an update on the operations and management of G20 today.
"She was very impressed with the policing response so far and the work the Metropolitan police are doing to make this a safe and secure G20."
* A man who died after being found collapsed at the G20 protests in the City was named by police today. Ian Tomlinson, 47, a City resident, was on his way home from work at a newsagent's when he collapsed near the Bank of England just before 7.30pm yesterday. A Metropolitan Police spokesman said officers had to move the casualty away for urgent treatment after bottles were thrown at them by protesters. He was later pronounced dead at hospital.
A spokesman for the Independent Police Complaints Commission (IPCC) said: "When all the available information has been assessed, the IPCC will make a decision about the level of involvement it needs to have in progressing the investigation into this case."
* The French "Spiderman" Alain Robert climbed the Lloyd's of London building today to protest over climate change. He unfurled a banner warning of "100 months" to save the world. Onlookers said he leapt out of a silver car which pulled up outside One Lime Street just before midday and began his ascent, without ropes, on the Leadenhall Passage side.
He reached the 9th floor of the 290ft-high building and unfurled a yellow banner before climbing down to street level, where he was met by police and led away.