Kenyan judges have criticised the "veiled threats" made by President Uhuru Kenyatta after the judiciary overturned his election on the ground that it was flawed.

Calling it "an assault on the judiciary", the Kenya Magistrates and Judges Association (KMJA) late on Saturday asked people to ignore "political rhetoric".

"The president of this country referred to the president of the Supreme Court and the other judges as "wakora", or crooks in Swahili, it said.

"He went on to make veiled threats against the same judges based on their decision. The same threats against the judiciary have been repeated at State House," said its chief Bryan Khaemba, referring to the presidential palace.

"We condemn this assault on the decisional independence of the honourable judges," he said.

READ MORE: Kenya president warns judiciary after vote nullified

Chief Justice David Maraga on Friday declared Kenyatta's victory in the August 8 polls "invalid, null and void", pointing to widespread irregularities in the electronic transmission of vote results.

An enraged Kenyatta said he respected the decision but lashed out against the judges, saying: "Every time we do something, a judge comes out and places an injunction. It can't go on like this ... there is a problem and we must fix it.

"I think those robes they wear make them think that they are more clever than the rest of us Kenyans," Kenyatta said of the Supreme Court judges, taking specific aim at Maraga.

"Maraga thinks he can overturn the will of the people. We shall show you ... that the will of the people cannot be overturned by a few people."

On Friday he slammed the judges as "crooks".

READ MORE: Why did Kenya's Supreme Court annul the elections?

This is the first time a presidential election result has been overturned in Africa and the decision has been welcomed by Kenyatta's challenger Raila Odinga, who has lost elections in 1997, 2007 and 2013.

Odinga, however, said he has no faith in the national election commission, which is tasked with organising elections in the next 60 days.

Kenyan media have hailed the ruling as a hard-fought victory for the rule of law, and a sign of a maturing democracy.