Tony Blair will close his advisory firm after making millions of pounds from an array of controversial clients ranging from oil companies to the authoritarian government of Kazakhstan.

But the jet-setting former UK prime minister intends to retain an unspecified number of private clients in a personal capacity, including JPMorgan, the US investment bank.

He will also continue to make speeches for corporate clients, for which he has charged up to £237,000 ($A407,450) a time.

After leaving office in 2007 Mr Blair swiftly built up a convoluted empire mixing lucrative advisory work with a handful of charities.

Tony Blair Associates has worked for a range of clients, including Kuwait, Vietnam, Peru, Colombia and Mubadala, an Abu Dhabi investment fund - although the former Labour leader has never been forthcoming about his client roster.

TBA made profits of £2.6m on turnover of £19.4m (up from £14.2m) last year after a period of rapid growth, according to the accounts of one of his subsidiary companies.

In a statement released this week, Mr Blair announced the closure of both Tony Blair Associates and its underlying structures under the names "Firerush" and "Windrush".

The "substantial financial reserves" of TBA - roughly £8.9m according to the accounts - would now be given to his not-for-profit activities, he said.

Richard Murphy, a tax campaigner, said the origins of that money were unclear. "I hope the organisations that are receiving it will do a little due diligence to make sure they're happy with the source of those funds," he told the Financial Times.

Mr Blair's statement said his organisations employed 200 people working in more than 20 countries.

"It is time to take this to a new level," he said. "I want to expand our activities and bring everything under one roof. I also want now to concentrate the vast bulk of my time on the not-for-profit work which we do."

Mr Blair admitted that he would retain a "small number of personal consultancies" for his income but insisted that not-for-profit work would take up 80 per cent of his time.

There would be an unspecified number of redundancies, a spokeswoman said, while some staff would transfer from commercial activities to not-for-profit work.

TBA operates out of Grosvenor Square in Mayfair, London, one of the most expensive office locations in the world. All the Blair-related organisations will in future work from a new premises, he said.

The spokeswoman played down the idea that the restructuring could mark a potential return to frontline politics for Mr Blair, who won three general elections for New Labour. The party has shifted markedly to the left since his time at the helm of the party.

Paul Flynn, shadow leader of the House, said: "He's yesterday's politician, part of our past and not our future."

Mr Blair has grown frustrated over the years by the focus on his opaque business activities rather than his not-for-profit work.