Chancellor Rachel Reeves is widely expected to increase taxes in her Budget on Wednesday to help fill a multibillion-pound gap in her spending plans.
Ministers had given strong indications the government was planning to increase income tax rates.
Anonymous briefings to the media from government sources had also suggested Reeves was considering the move - which would have been a clear breach of Labour's election promise not to raise "the basic, higher or additional rates of income tax".
However, last week government sources said Reeves had decided against this after better-than-expected economic forecasts.
Governments sometimes choose to leak aspects of their Budget plans to the media, either to test public reaction or prepare the ground for measures so they do not come as a shock to financial markets or voters.