The weekly mass demonstrations — among the largest seen in South Korea since the pro-democracy protests of the 1980s — have provided a stark challenge to Park’s authority, but the president has defied calls to step down.

After claiming a turnout of around one million for last Saturday’s protest, organisers said they expected around 500,000 people to march in Seoul, with a similar number demonstrating in other cities across the country.

So far the candlelight protests have been largely peaceful, with many families participating, but there was still a heavy police presence on Saturday, with buses and trucks blocking access roads to the presidential Blue House.

“We want to have a peaceful protest as in the three previous rallies”, Nam Jeong-Su, spokesman for the Korean Confederation of Trade Unions, told AFP.

Nam said he expected the ranks of protestors to be swelled by thousands of students who sat the national college entrance exam earlier in the week.

And this being South Korea — with the world’s highest smartphone penetration rate — many had downloaded a special app showing a burning candle to hold aloft during the rally.

Protestors were expected to converge on Seoul’s ceremonial Gwanghwamun boulevard at around 5:00pm (0900 GMT) to hear speeches before heading towards the Blue House and the police barricades.

– Apologies rejected –

The anti-Park rallies have continued despite two televised apologies from the president over a scandal linked to her friendship with long-time confidante Choi Soon-Sil, who has been arrested for fraud and abuse of power.

Prosecutors are investigating allegations that Choi, 60, leveraged their friendship to coerce donations from large companies like Samsung to non-profit foundations which she set up and used for personal gain.

She is also accused of interfering in government affairs, despite holding no official position.

Lurid reports of the unhealthy influence Choi wielded over Park have seen the president’s approval ratings plunge to five percent — a record low for a sitting president.

In an effort to soothe public anger, Park has agreed to relinquish some of her extensive presidential powers and submit to a probe by an independent special prosecutor to be appointed by parliament.

But she has made it clear she has no intention of resigning and some members of her ruling Saenuri Party have started to push back at the popular protests of the past month.

“Candles are candles. They will just go out with a gust of wind,” one Saenuri lawmaker said.

The scandal has paralysed the Park administration and caused the president to pull out of a gathering of Asia-Pacific Economic Cooperation (APEC) leaders in Peru next week.

But after a lengthy hiatus, Park has visibly returned to normal duties and announced she will attend an annual summit with China and Japan in Tokyo next month.

The presidential Blue House said Park was receiving baskets of flowers from supporters, and organisers of a pro-Park rally near Gwanghwamun said they expected 5,000 people to turn out.

Police said they would keep the two rallies well separated to prevent any clashes.