A jury in Hong Kong has watched a chilling video of a British banker describing how he killed an Indonesian woman he met in a bar, saying he repeatedly raped her and "tortured her badly".

In an iPhone video he shot, Rurik Jutting, a Cambridge University graduate on trial in Hong Kong's High Court for the murder of two Indonesian women, can be seen shirtless in his apartment.

"My name is Rurik Jutting. About five minutes ago I just killed, murdered, this woman here," he says into the camera, pointing it down briefly to show the body of Sumarti Ningsih, 23, lying face down on the floor of his bathroom shower.

Moments later he holds up his hand, which can be seen shaking.

"It's Monday night. I've held her captive since early Saturday, I've raped her repeatedly, I tortured her, tortured her badly."

Later on, her body is seen wrapped in a grey blanket, with her legs sticking out of it and streaks of blood on the floor. Jutting tells the camera it was "several hours" after he killed her.

It was part of an extended, rambling monologue which continued for hours over several video clips in which Jutting discussed his use of drugs and prostitutes, whether to commit suicide and how he felt no guilt after killing Ms Sumarti.

The graphic video was shown on the second day of Jutting's trial for murdering Ms Sumarti and Seneng Mujiasih, 26, whom prosecutors say Jutting killed by slitting their throats.

Their bodies were found in his luxury apartment near the Asian financial centre's Wan Chai red-light district in 2014 in a case that shocked the city, which has a reputation for being safe but also has extreme inequality among its foreign workers.

The former British colony has a sizeable white-collar expatriate elite alongside more than 300,000 migrant domestic workers, almost all of them women from Indonesia or the Philippines.

Jutting, who worked in the Hong Kong office of Bank of America-Merrill Lynch in structured equity finance and trading, pleaded not guilty on Monday to two murder charges, with prosecutors rejecting his attempt to plead guilty to the lesser charge of manslaughter. If convicted, he faces life in prison.

Jutting, 31, watched the proceedings from the glass-screened dock, with a blank expression. He wore a pale blue shirt and appeared much slimmer than in court appearances last year.

Earlier, the jurors were played about 20 minutes of video in which Jutting is apparently torturing Ms Sumarti. The media and public could not view it, but were able to hear the audio.

At one point he can be heard saying: "If you scream I will punish you. Understand?"

That is followed by the sound of smacking and slapping.

During his monologue, Jutting said "I've always had dark fantasies" involving rape, torture, murder.

He said he had earned more than a million US dollars from his bank job over the previous two years but had spent most of it on drugs and prostitutes.

At one point, he holds up to the camera a small plastic bag apparently containing cocaine and a rolled up 10 Hong Kong dollars bill. He is seen several times in the video clips snorting the drug.

In opening remarks on Monday, prosecutor John Reading told the court that Ms Sumarti, who was in Hong Kong on a tourist visa, went home with Jutting after he offered her "a large sum of money".

After she died, Jutting put her remains in a suitcase he left on the balcony.

Ms Seneng was officially in Hong Kong as a foreign maid but was working at a bar when Jutting met her and after offered her money for sex days after killing Ms Sumarti, the prosecutor said.