Three out of 10 taxpayers in Scotland could be facing a rise in their bills after Thursday's Scottish Budget, the First Minister has indicated.
Nicola Sturgeon added however her government would seek to "protect those on low and middle incomes".
But she said there was a need to "protect our vital public services" ahead of Holyrood's Budget, which is widely expected to include income tax rises for some higher earners.
Finance Secretary Derek Mackay will unveil the Scottish Government's tax and spending plans for 2018-19 on Thursday.
Ahead of his Budget statement the First Minister said: "I can tell the chamber today that 70% of taxpayers in Scotland - 83% of all adults in Scotland - will pay no more income tax after this Budget than they do now."
Speaking about the draft Budget, the SNP leader said the "vast majority" of taxpayers would be "protected" from any increase in taxes.
But Scottish Conservative leader Ruth Davidson, who pressed her on the issue at First Minister's Questions, recalled how the First Minister had committed to not increasing the basic rate of income tax for the entire parliamentary term.
As a result she said any increase for some in this group would mean taxpayers would be unable to "ever trust her again".
Ms Sturgeon insisted: "We will set out fair, balanced, progressive Budget proposals that protect our public services from more than £200 million in real terms of cuts being imposed by the Tories.
"Our spending is being cut by more than £200 million in real terms next year, and the proposals we put forward this afternoon will set out how we protect our NHS our education system and other vital public services from that, while protecting the vast majority of tax payers and also investing in business and the economy."
Ms Davidson quoted the First Minister as having pledged that "when inflation is rising and living standards are under a lot of pressure it is not right to increase income tax for those who are on the basic rate".
She added: "Those were the direct words of the First Minister herself, just this year in May.
"What I was asking her was whether she agreed with herself that all people who currently only pay the basic rate of income tax, which is 2.2 million people in this country, shouldn't have to pay more, because that was the promise she made."
But after Ms Sturgeon 70% of taxpayers would not pay any more, the Tory hit out: "Hasn't she just told at least some of them that she is breaking her promise."
She continued her attack, saying: "Time and time again ahead of elections the SNP Government make promises to people on tax.
"And it was only in May of this year the First Minister was absolutely clear - it is not right she said for any person on the basic rate to pay more.
"That is 2.2 million people in this country that would be protected and she's just stood up and said some of them are going to take a hit.
"This is simple matter of trust, promises were made, she's failed to meet them, so how can Scottish workers ever trust her again?"