The UK's tax authority is stressing that "no laws have changed" and that tax rules remain the same following the EU referendum.
Changes to financial regulations will inevitably change in time following the UK's vote to leave the EU.
But, a recorded message on the HM Revenue and Customs (HMRC) helpline says that nothing has changed in the immediate aftermath of the vote.
An accountancy group said the reassurance message was sensible.
The HMRC message says: "There are no changes to any taxes, tax credits, child benefits or other HMRC services as a result of the vote on the EU referendum.
"Everything is continuing as normal. No laws have changed. There is no need to contact HMRC as a result of the EU referendum."
The recorded message was added to the helpline in line with plans made before the vote, not in response to calls from taxpayers, the tax authority said.
A change of prime minister and new look to the government is likely to lead to tax changes, said Chas Roy-Chowdhury, head of taxation at the ACCA accountancy body, but he added that nothing had changed straight away.
"People and businesses still need to get returns in or make tax payments - they can't slack under the fog of the referendum result," he said.
There is no "moratorium on deadlines", he said, with the next tax deadline for half-year tax payments for those in the self-assessment system coming on 31 July.
He added that there was a danger that if businesses, in particular, were not urged to carry on as normal, that the UK could "talk itself into a recession".