The government is to set up a new task force to investigate allegations of tax-dodging and money laundering in light of the Panama Papers leak.
The unit will be led by HM Revenue and Customs and the National Crime Agency.
It will also include specialists from the Serious Fraud Office and the Financial Conduct Authority.
It was announced by Prime Minister David Cameron as he released details of his tax returns in an effort to defuse a row over his financial affairs.
The move is also being seen as an effort by Mr Cameron to regain the initiative on the issue of tax avoidance, after attention focused on his own involvement with his late father's offshore fund, Blairmore Holdings.
A Treasury spokeswoman said the task force would report on progress to Chancellor George Osborne and Home Secretary Theresa May later this year.
She said it would have "a strong operational focus" and would include analysts, tax and financial investigators and other specialists.
However, it will not automatically be entitled to examine the leaked files from Panamanian lawyers Mossack Fonseca that are at the heart of the revelations.
The Treasury said HMRC had asked the International Consortium of Independent Journalists, including the BBC and the Guardian newspaper, to share their data.
Analysis: Kamal Ahmed, economics editor
One person's tax planning is another person's tax avoidance - so whether David Cameron's tax affairs are controversial or not is really a matter of where you stand on the payment of tax.
Most tax accountants would advise a wealthy family on "gifts" - payments of money - to their children and how to ensure they are not liable for inheritance tax by making payments in tranches to avoid breaching tax thresholds.
Mr Cameron's family appear to have done this, and Downing Street says the payments were made by the Prime Minister's mother to "even out" the inheritance payments made to her children following her husband's death.
Not to avoid tax.
"So far they haven't done so," said the spokeswoman, "and the government is calling on them again to hand over the information that they hold."
She said HMRC could protect the confidentiality of any source.
The Treasury said it was "too early to say" what the ultimate goal of the task force would be and whether new legislation would be needed as a result.
The summary of Mr Cameron's tax returns shows he paid almost £76,000 in tax on an income of more than £200,000 in 2014-15.
He was also given two payments of £100,000 by his mother a year after inheriting £300,000 from his father.
The payments by Mary Cameron to her son in May and July 2011 were given tax-free and will only become liable to inheritance tax of up to 40% if she dies within seven years of handing over the money.