At the moment those who fail to tell the taxman about inherited offshore assets are treated equally to those who fail to disclose domestic assets. However new penalties of up to 200% of tax due will be introduced in the next session of parliament.
It is thought by the Treasury that the current system encourages people to leave offshore assets out of an inheritance tax account in the hope that the worst that can happen should they be discovered is a ticking off and a 100% penalty.
Under new plans the government is set to make offshore evasion a criminal offence so those with undisclosed assets abroad who are caught out are liable to be fined 200% of tax lost as well as criminal prosecution.
HMRC is also considering suspending the current 20 year rule which caps the period during which deliberate offshore evaders of tax can be investigated and which is thought to have lost huge sums of tax in the past.
The changes come on top of those recently proposed by George Osborne to prosecute people found to have undeclared foreign income even although they did not deliberately intend to avoid payment.