Kenyan President Uhuru Kenyatta has announced he and his deputy William Ruto will be taking a 20-percent pay cut and ministers' salaries will be reduced by 10 percent in a bid to rein in the country's soaring public wage bill.

The pay cuts will take place "with immediate effect," Kenyatta said in a speech on Friday, adding that the current spending levels were unsustainable.

The government will also limit foreign travel to only the most essential trips, according to Kenyatta. "Wastage in my government will be significantly reduced," he said.

"We are spending 400 billion shillings ($4.6 billion, 3.3 billion euros) every year paying salaries; it leaves us only from our own resources a figure of 200 billion shillings to transform Kenya," Kenyatta said.

"This is why we are saying that is the ratio which is not sustainable... We need to deal with this monster if we are to develop this nation."

The president urged the country's lawmakers to follow his lead and also lower their salaries, ranked among the highest in the world and long a source of discontent among ordinary Kenyans.

"We hope that other arms of government will follow suit and have their salaries reviewed. The MPs have heard and know what Kenyans want," Kenyatta said.

MPs last year reluctantly took a 40-percent pay cut, bringing their monthly pay checks down to around 532,000 shillings ($6,100, 4,400 euros).

The lawmakers had initially voted to give themselves a pay rise, sparking protests from activists, before agreeing to accept the salary reduction ordered by the Salaries and Remuneration Commission in return for other benefits.

Kenya's lawmakers also sparked controversy in 2012 by voting to give themselves a sendoff bonus of $110,000, a proposal that was vetoed by then-president Mwai Kibaki.

According to the Standard daily, Kenyatta, whose family is one of the continent's wealthiest, will see his monthly income reduced to about 989,600 shillings, while Ruto's will be lowered to 841,500 shillings.

The combined savings will leave the state some 5.5 million shillings a year better off, the Standard said.

The minimum wage in Nairobi for a manual labourer is around 8,500 shillings a month.