Theresa May says she will not be making “specific proposals” on taxes unless she is “absolutely sure” they can be delivered.
The PM was asked about the 2015 Tory pledge that certain taxes would never be raised, but declined to repeat it.
She added that her intention was to cut taxes for working families.
Speaking on the BBC’s Andrew Marr show, she also rejected claims she was “in a different galaxy” to the rest of the EU on Brexit negotiations.
Asked whether she would be repeating ex-PM David Cameron’s “five-year tax lock”, covering income tax, National Insurance and VAT until 2020, Mrs May said: “We have absolutely no plans to increase the level of tax.
“But I’m also very clear that I do not want to make specific proposals on taxes unless I am absolutely sure that I can deliver on those.”
Speaking later on the Peston on Sunday show, she ruled out a VAT rise, saying “we won’t be increasing VAT”.
On the Marr show, the PM suggested the “triple lock” protecting the state pension could be changed, saying state pensions would continue to rise, with the exact method of calculations that is calculated to be revealed in the Tories’ manifesto.
The triple lock ensures the state pension increases in line with wages, inflation or by 2.5% – whichever is highest.
And after the 27 EU leaders agreed their Brexit negotiations, the PM said there was “good will” on both sides about settling the issue of EU nationals living in the UK, and Britons elsewhere in Europe.
She said recent comments by EU figures showed that talks could be hard, and stressed her determination to reach agreement on a trade deal at the same time as settling the terms of the UK’s exit.