Even as the NASA leader dug in, Prof Muigai, the chief legal advisor to the Government, convened a press conference to warn Raila that he risked arrest should he make true his threat.
Kenya's opposition leader has rejected U.S. advice to cancel a planned mock inauguration of him as president, saying he does not recognise the legitimacy of President Uhuru Kenyatta.
He said such an inauguration would be outside the Constitution because Kenya already has a sitting president who took the oath of office on November 28.
Any person who takes part in such an inauguration, he said, will face the law.
"Any attempts to swear in any person as president other than the one elected in line with the constitution and in a manner provided for in the law is unlawful, illegal null and void", Muigai told reporters.
Mr Odinga has insisted that he won the August 8 presidential poll and accuses the Independent Electoral and Boundaries Commission (IEBC) of rigging him out.
Some 11 counties have so far passed the people's assemblies as directed by Nasa and Mr Odinga could be sworn in in any of them.
Arrest Made 7 Years After NBA Player Lorenzen Wright's Murder
Wright called 911 from his cellphone from a field near the TPC Southwind golf course minutes after midnight on July 19, 2010. For his career, Wright averaged 8.0 points and 6.4 rebounds per game over a grand total of 778 regular season contests.
He said the national government retains the right to review the funds allocated to the concerned counties.
However, speaking in Nairobi on Thursday, Odinga told off Western countries led by the United States, who have been piling pressure in him to shelve the swearing in plan.
"The United States urges opposition leaders to work within Kenya's laws to pursue the reforms they seek and to avoid extra-constitutional actions such as the proposed "inauguration ceremony" on December 12", the U.S. Embassy said in a statement.
Lone said Odinga has also always been open to a dialogue as he had sought it before elections to ensure that it would be credibly done, but there was no interest in the dialogue nor in holding an honest election.
"Countries saying they are friends of Kenya have remained silent since August 8, over 205 people have been killed, and not even a single person has talked", Raila said although he did not provide evidence of the death toll. "Kenyan problems can only be solved by the people of Kenya", said Mr Odinga.
He spoke at the City Mortuary in the capital Nairobi when he met and condoled with families that lost their loved ones during the post-poll chaos.