South Korean President Park Geun-Hye has met prosecutors for questioning over a corruption scandal that toppled her, after using executive privilege to avoid them for months while in office.

Park apologised to the public as she arrived at the prosecutors' office in Seoul on Tuesday, adding: "I will undergo the investigation sincerely."

South Korea's first female president, Park was impeached by parliament in December after millions of people took to the streets to demand her removal over the sprawling scandal, which exposed deep links between politics and business.

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Her dismissal was confirmed by the country's top court earlier this month, ending the political career of a woman who grew up in the presidential palace as the daughter of army-backed ruler Park Chung-Hee.

Questioning by prosecutors is a key step in South Korea's judicial process before a suspect is charged. It can last for many hours, late into the night, and can be repeated if officials deem it necessary.

Park, 65, faces a number of charges from abuse of power to bribery, and is the fourth former South Korean leader to be probed or jailed over corruption scandals.

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Al Jazeera's Rob McBride, reporting from Seoul, said that Park's opponents has been criticising her for avoiding questioning for months.

"Now that her immunity is gone, she cannot avoid those questions," he said. 

"Prosecutors have a tough job here. They finally got the chance to ask Park the questions they wanted to ask for months. But they know that they have to treat Park as a former president with respect."

McBride said prosecutors had 300 questions for the former president, which would take about 10 hours to answer.

The secret confidante

Park has been named as an accomplice Choi Soon-Sil, a confidante at the heart of a scandal that has also seen Samsung heir Lee Jae-Yong arrested and charged with bribery.

Choi is accused of using her presidential ties to force local firms, including Samsung, to donate nearly $70m to non-profit foundations she allegedly used for personal gains.

Park is accused of offering governmental favours to business tycoons who enriched Choi, including Lee.

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The former leader is also accused of letting Choi, who has no official title or security clearance, handle a wide range of state affairs including the nomination of top officials or diplomats.

The ex-president has repeatedly denied any wrongdoing and blamed Choi for abusing their friendship. Choi is currently on trial on charges that include abuse of power and coercion.

Park won the presidential vote in 2012 largely thanks to the popularity of her late father among the aged, conservative voters who benefited from the rapid growth under his iron-fisted rule from 1961 to 1979, but the scandal sent her once-bulletproof support ratings to record lows.

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Source: Al Jazeera and news agencies