David Cameron will put tackling corruption at the "top of the international agenda", he said ahead of a London summit on the issue.
The international anti-corruption summit - the first of its kind - is aimed at exposing, punishing and drive out global corruption.
Prior to the summit, the Prime Minister described corruption as "the root of so many of the world's problems".
Among those he cited corruption as fuelling terrorism.
World leaders attending the summit include the presidents Ashraf Ghani of Afghanistan, Juan Manuel Santos of Colombia, Muhammadu Buhari of Nigeria and Norwegian prime minister Erna Solberg.
Mr Cameron hopes that countries will sign a global declaration committing them to tackling corruption, ensuring it is not allowed to fester in institutions, businesses or communities and supporting people affected by it.
The summit was planned before the Panama Papers leaks revealed details of tax-dodging schemes used by wealthy individuals, political figures and companies, but the revelations have added pressure to act.
Campaigners have called for a crackdown on tax havens linked to the United Kingdom and Downing Street said it expected "a number" of overseas territories to attend.