Jeremy Corbyn has blamed the Cabinet Office and "media barons" for confusion over his tax return, 18 hours after questions were first raised about his income.
The Labour leader released a furious statement branding media reports that he may have failed to declare part of his income "false".
His spokesman said: "We are disappointed the Cabinet Office did not clarify this and explain the figure used on the P60 yesterday in answer to media inquiries they received.
“It is also a matter of concern that some media organisations made entirely false claims without verifying or confirming the facts, and we expect these now to be corrected.
“The owners of the media companies that have attempted to cast doubt over Jeremy’s transparent and accurate tax return are of course among those who could stand to lose from the tax transparency and justice the British people demand.
“Jeremy believes firmly in transparency. These media barons have tax questions of their own to answer."
A spokesman for the Prime Minister said Mr Corbyn's tax return is a matter for the Labour party, not the Government.
HMRC did not comment.
Mr Corbyn insisted earlier that nothing had been "hidden" from his tax return amid allegations that he failed to declare £30,000 he earned as Labour leader.
Labour said Mr Corbyn was paid an additional £27,192 on top of his MP's salary in the year 2015/16.
However, Mr Corbyn was paid £30,587 for for his role as Opposition leader in 2015-16, according to the government annual accounts.
Last night Mr Corbyn was facing claims he may have failed to declare income on his tax return last night after it appeared to show that he did not take a salary as Labour leader.
Transparency invites scrutiny. I welcome it as should all those seeking highest office. My taxes fully paid, nothing missing, nothing hidden— Jeremy Corbyn MP (@jeremycorbyn) March 6, 2017
The additional salary was missing from his official declaration to HM Revenue and Customs and aides were unable to explain the omission.
But in a statement published after midnight Labour said the allowance of £27,192 was included under the pension and benefits income.
In a post on Twitter this morning, Mr Corbyn added: "Transparency invites scrutiny. I welcome it as should all those seeking highest office. My taxes fully paid, nothing missing, nothing hidden."
Hours after Philip Hammond refused to publish his tax return Mr Corbyn published his documents for 2015/16 in a bid to put pressure on the Chancellor to change his mind.
But he declared £77,000 in salary and allowances and £36,000 in pensions income when he should have earned around £150,000 including his pay for being leader of the party.
A Labour spokesman said: "The extra payment following Jeremy's election as Labour leader of £27,192 is recorded in the tax return under the heading of 'public office'.
"We are confident the total income of £114,342 in the tax return is correct, as is the income tax charge of £35,298. Nearly all the tax was paid at source."
Last year Mr Corbyn failed to declare his three pension incomes properly and faced criticism for sending the document to HMRC late, incurring an £100 fine.
The party leader has a state pension, union income and a pension from his time in local government.
This year he employed an accountant to complete the form which stated that the party leader made £114,342 overall and paid £35,298 in tax.
Over £77,000 came from his salary as an MP, made up of £73,284 in basic pay and £3,759.96 from a London allowance to account for extra expenses incurred by MPs living in the city.
A Labour source said Mr Corbyn had used accountants to examine his tax situation, adding: "We are absolutely confident Jeremy has paid all his tax, because it is taxed at source."
Labour said it welcomed media and public scrutiny of the Labour leader's tax return "as a matter of policy, not political point scoring".
Diane Abbott, the shadow home secretary, told BBC Radio Four's Westminster Hour: "He couldn't possibly be intending to deceive anybody."
Asked if she would release her tax returns, she said: "I think we are going to have to discuss this as a shadow cabinet if we all going to publish our tax receipts. If that's what we agree to do, certainly I'll do it."