It has already held cost-of-living protests this year and is threatening further demonstrations

"Our position remains that the bill is a mistake and an experiment Kenyans can ill afford," a spokesman for opposition leader Raila Odinga is quoted by AFP as saying.

"We had hoped that Ruto could call for its review before signing it."

Among the changes agreed by parliament last week were a doubling of the sales tax on fuel, from 8% to 16%, and a new housing levy.

The new measures have angered some supporters of the president, who during his successful election campaign presented himself as someone who would look out for the interests of the poor.

Mr Ruto has defended the changes as necessary to deal with the country’s debt problem and as a means to invest in programmes that will benefit the less well off.