Park refuses questioning by prosecutors - lawyer

Prosecutors describe Park and her secret confidante, Choi Soon-Sil, as co-culprits in the scandal. They are accused of coercing top Seoul firms to donate over $60 million to non-profit foundations which Choi then used for personal gain.

Choi was charged last week with coercion and abuse of power.

The scandal has sparked nationwide fury, with hundreds of thousands taking to the streets to call for Park's ousting.

A parliamentary vote to impeach her could take place as early as this week as a growing number of ruling party politicians back the opposition-led campaign to oust the president.

Park earlier vowed to cooperate "sincerely" with the legal probe but has rejected a series of requests in recent weeks by prosecutors to make herself available for questioning.

"We regret that we can't cooperate with the request from prosecutors to hold face-to-face questioning on November 29," Yoo Young-Ha, Park's lawyer, told reporters.

Seoul prosecutors gave Park an ultimatum last week, saying Tuesday is the final deadline for questioning before a powerful independent team of investigators takes over the probe in December.

But Park -- the first South Korean president to become a criminal suspect while in office -- is too busy handling state affairs and preparing a legal defence against the mounting accusations, Yoo said.

It is not clear whether Park will cooperate with the new independent investigative team.

As a sitting president, Park cannot be charged with a criminal offence except insurrection or treason, but she can be investigated and potentially charged once her term is over.

The president is also accused of letting Choi, daughter of a shady religious figure who was a longtime mentor to Park, meddle in state affairs including the nomination of top officials.