The website of the Mossack Fonseca law firm, on Monday. (Reuters photo)

The Anti-Money Laundering Office (Amlo) is seeking information from its foreign counterparts regarding 21 Thai nationals reportedly included in a list of people worldwide using a Panama-based law firm for money laundering and tax evasion.

Pol Col Seehanat Prayoonrat, the acting Amlo secretary-general, made the comments following a report by the International Consortium of Investigative Journalists (ICIJ) which cited leaked documents from law firms that have been assisting politicians and leaders worldwide - including the 21 Thai nationals - to carry out the illicit acts.

He said he has so far obtained information only from the media.

Normally, any country that detects money laundering carried out by an individual of another nation must share their information with authorities of that country, he said.

He added he could not say how long it would take to obtain such information.

Government spokesman Sansern Kaewkamnerd said Prime Minister Prayut Chan-o-cha was aware of the reports.

Tax authorities in Australia and New Zealand are probing local clients of a Panama-based law firm and Asean parliamentarians are calling for a crackdown on corporate tax evasion following a massive data leak detailing hidden bank accounts and shadow companies used by the rich and powerful worldwide.

Other jurisdictions are likely to follow suit following the leak over the weekend of details of hundreds of thousands of clients in more than 11.5 million documents from the files of law firm Mossack Fonseca, based in the tax haven of Panama.

The documents are at the centre of an investigation published on Sunday by the International Consortium of Investigative Journalists and more than 100 other news organisations around the globe.

The German newspaper Sueddeutsche Zeitung said it received the huge cache of documents and shared them with the other media outlets.

The leaked "Panama Papers" cover a period over almost 40 years, from 1977 until last December, and allegedly show that some companies domiciled in tax havens were being used for suspected money laundering, arms and drug deals and tax evasion.

"I think the leak will prove to be probably the biggest blow the offshore world has ever taken because of the extent of the documents," said Gerard Ryle, director of the International Consortium of Investigative Journalists.

Britain's Guardian newspaper said the documents showed a network of secret offshore deals and loans worth US$2 billion led to close friends of Russian President Vladimir Putin. Reuters could not independently confirm those details.

Kremlin spokesman Dmitry Peskov did not immediately respond to a request for comment from Reuters on Monday. Andrey Kostin, chief executive officer of VTB Group, Russia's second-largest lender, told Bloomberg News the accusation was nonsense.

This combination of pictures created on April 4 shows six world leaders (top from left) Argentinian President Mauricio Macri, Emirati President Sheikh Khalifa bin Zayed al-Nahayan, and Saudi King Salman bin Abdulaziz, Ukraine President Petro Poroshenko and Prime Minister of Iceland Sigmundur David Gunnlaugss, whose names are featured in a massive leak of documents, some of which revealing hidden offshore assets involving Panama-based law firm Mossack Fonseca. (AFP photo)

Last week, Mr Peskov said reports about the financial dealings of concert cellist Sergei Roldugin, a friend of Mr Putin, and other related reports, were part of a politically motivated campaign to discredit Putin ahead of a cycle of elections.

The Australian Tax Office (ATO) said it was investigating more than 800 wealthy clients of Mossack Fonseca.

"We have now linked over 120 of them to an associate offshore service provider located in Hong Kong," the Australian tax office said in a statement. It did not name the Hong Kong company.

ATO deputy commissioner Michael Cranston said his office was working with the Australian police and the anti-money laundering regulator Austrac to cross-check the data, and some cases may be referred to the Serious Financial Crime Taskforce.

The 800 individuals under investigation include taxpayers who had previously been investigated and others who had reported themselves to the tax office under a voluntary disclosure initiative which allowed people to come forward and avoid steep penalties and criminal charges and has since ended.

However, the ATO said those under investigation also included many taxpayers who had not previously come forward.

Asean response

The Associated Press reported that a group representing current and former lawmakers from Southeast Asian countries says the trove of leaked documents shows how the wealthy and politically powerful have abused rules governing offshore tax havens, often to the detriment of their own communities.

The Asean Parliamentarians for Human Rights is calling for governments in the region to crack down on large scale corporate tax evasion and pursue more equitable tax regimes.

Malaysian lawmaker Charles Santiago, who chairs the group, says multinational corporations and individuals evading tax should be hauled up in their respective countries.

"Intermediaries, especially financial institutions, must be investigated and charged as well," he said.

Worldwide inquiries

Elsewhere, the British government asked on Monday for a copy of leaked data on the clients of the law firm so it can examine the information and act on any possible tax evasion.

The late father of Prime Minister David Cameron, who has spoken out against a crackdown on tax evasion and tax avoidance, is mentioned in the documents, alongside some members of his Conservative Party in the upper house of parliament, former Conservative lawmakers and party donors, British media said.

French President Francois Hollande speaks to employees as he visits a tech company in Boulogne-Billancourt, outside Paris, on April 4. Mr Hollande promised that a massive leak of documents exposing the offshore dealings of wealthy individuals would lead to legal proceedings in France. (AFP photo)

In France, Prime Minister Francois Hollande promised mass investigations of French nationals named in the documents while Austria's financial markets regulator FMA is investigating whether lenders Raiffeisen Bank International and Hypo Landesbank Vorarlberg followed rules against money laundering after they were named in a the data leak, AFP reported.

In Sweden, the Financial Supervisory Authority has contacted authorities in Luxembourg to ask for information related to allegations that banking group Nordea helped some clients to set up accounts in offshore tax havens.

'Limited hack'

The head of Mossack Fonseca has denied any wrongdoing but said his firm had suffered a successful but "limited" hack on its database. The firm's director, Ramon Fonseca, described the hack and leak as "an international campaign against privacy".

Fonseca, who was up until March a senior government official in Panama, said in a telephone interview with Reuters on Sunday the firm, which specialises in setting up offshore companies, has formed more than 240,000 such companies. The "vast majority" of these have been used for "legitimate purposes", he said.

The papers also showed the involvement of Pakistini Prime Minister Nawaz Sharif's family in off-shore companies, including his daughter Mariam and son Hussain. Pakistani Information Minister Pervez Rasheed denied any wrongdoing on the Sharifs' part.

"Every man has the right to do what he wants with his assets, to throw them in the sea, to sell them, or to establish a trust for them. There is no crime in this in Pakistani law or in international law," Mr Rasheed said.

Hussain Nawaz, speaking to Geo TV, also said there was nothing illegal either about the family's ownership of the companies, or about the activities of the companies themselves.

A 2009 file picture shows a general view of high-rise buildings in Panama City,. Millions of leaked documents published on April 3 suggest that 140 politicians and officials from around the globe, including 72 former and current world leaders, have connections with secret “offshore” companies to escape tax scrutiny in their countries. (EPA photo)

"I have never hidden anything and neither do I have any need to hide them...these companies are allowed under British law so that one does not need to pay unnecessary taxes," he said.

New Zealand's tax agency said it was working closely with its tax treaty partners to obtain full details of any New Zealand tax residents who may have been involved in arrangements facilitated by Mossack Fonseca.

Separately, media reports said the leaked data pointed to a link between a member of global soccer body Fifa's ethics committee and a Uruguayan soccer official who was arrested last year as part of a US probe into corruption in the sport.

Fifa's ethics committee said on Sunday that Juan Pedro Damiani, a member of the committee's judgment chamber, was being investigated over a possible business relationship with fellow Uruguayan Eugenio Figueredo, one of the soccer officials arrested in Zurich last year.

Mr Damiani told Reuters in Montevideo he broke off relations with Figueredo when the latter was accused of corruption.