COLOMBO (AFP) - Sri Lanka's President Mahinda Rajapakse has nominated the government's senior legal advisor Mohan Peiris as a replacement for the impeached chief justice, his spokesman said on Tuesday.

Mr Peiris is scheduled to take his oath of office shortly after a parliamentary panel confirms his appointment, spokesman Mohan Samaranayake said.

"I can confirm now that Mohan Peiris will be the new chief justice," said Mr Samaranayake. "Immediately after the affirmation from parliament, he will take his oath."

Mr Peiris retired two years ago as attorney general, but has since been the senior legal advisor to the cabinet in addition to being a key defender of Sri Lanka's record at United Nations rights meetings.

His appointment comes after the president approved Ms Shirani Bandaranayake's dismissal on Sunday, two days after lawmakers voted for her impeachment.

Judges have declared the impeachment of Ms Bandaranayake, the first woman chief justice, to be illegal and unconstitutional.

The United States reiterated its concerns on Monday when State Department spokesman Victoria Nuland said the impeachment "raises serious questions about the separation of powers in Sri Lanka, which is a fundamental tenet of a healthy democracy".

Lawmakers found Ms Bandaranayake guilty of tampering with a case involving a company from which her sister bought an apartment, of failing to declare dormant bank accounts, and of staying in office while her husband faced a bribery charge.

She had said the charges were politically motivated and she was denied a fair trial. Her lawyers have vowed to contest her removal and resist the new chief justice.