Deputy Prime Minister Nick Clegg is to urge the coalition today to "go further and faster" in implementing an increase in the income tax threshold.
The coalition has promised to raise the threshold to £10,000 by the next election, set for 2015.
The threshold has been increased in recent years, firstly to £7,475 in 2010 and, later this year, it is set to be increased again to £8,105.
But Clegg will say later today that many families are at financial "boiling point" and need more relief, reports the BBC.
Clegg's speech to the Resolution Foundation comes ahead of the Budget on 21 March, increasing speculation that changes to tax thresholds could be announced.
He is expected to say: "Today I want to make clear that I want the coalition to go further and faster in delivering the full £10,000 allowance, because the pressure on family finances is reaching boiling point.
"These families have seen their earnings in relative decline for a decade, compared to those at the top. That has accelerated since 2008, with lower real wages and fewer hours at work."
Duo start roles on 1 October
Where true value lies
Economy to thrive despite global risks
Behaviours, animals or something else?