Shadow Chief Secretary Rachel Reeves says Labour will seek to force a vote on charity tax in the Commons on Wednesday.
"The truth is, at a time when the average family is taking a £511-a-year hit as a result of the Government's policies, they have given the 300,000 wealthiest taxpayers in the country a £3 billion tax cut.
A rushed-out cap on reliefs which will raise just £300 million, whilst hitting charities which help the most vulnerable, won't cover that up.
We will seek a vote to block these changes until the Government has done the work necessary to demonstrate they are being made in a way which will not hit charities and which will genuinely tackle avoidance."
The government appears to have tied itself in knots over the row on charitable giving.
The row over the cap on a tax relief for charitable giving is the latest in a string of rows that have erupted since the budget.
Charities and philanthropists have warned that Government plans to change the way it taxes charitable donations will discourage giving