Jutting, 31, had earlier today pleaded "not guilty" to two counts of murder on the grounds of diminished responsibility. He instead pleaded guilty to manslaughter.
The prosecution rejected the lesser plea and jury selection began.
As judge Michael Stuart-Moore briefed the jury pool at the High Court, he warned them of the graphic nature of the evidence.
He said that Jutting "recorded on his iPhone much of what he did to those people", and described the footage as "very shocking indeed".
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Mujiasih was found naked and with knife wounds to her legs and buttocks, while the decaying body of Ningsih was found hours later in a suitcase on the balcony, according to initial police reports.
Jutting, a former securities trader at Bank of America Merrill Lynch, faces a three-week jury trial and life in prison if convicted on the murder charges.
The killings shocked the city of seven million - typically regarded as safe and known for its glitzy skyscrapers - and shone a spotlight on the seedy underbelly of the financial hub.
Clean-shaven and wearing a dark-blue shirt, Jutting calmly entered his official plea for the first time today, saying: "Not guilty to murder by reason of diminished responsibility, but guilty to manslaughter".
He pleaded guilty to a third charge of preventing the burial of a body.
Outside the court, a small group of protesters from Indonesian migrant worker organisations called for a "speedy and fair trial" and for compensation for the victims' families.
It is the highest-profile murder case to hit the Hong Kong courts since American Nancy Kissel was accused of killing her banker husband in 2003.