Parents of a New Zealander on board the downed MH17 flight are among hundreds of grieving family members following the trial of those accused of causing the plane crash.

Although the trial began in March 2020, evidence heard in a Dutch courtroom about how the plane was shot down, allegedly due to the actions of four men in eastern Ukraine, only began last week.

Among those monitoring the high-profile trial is John and Wendie Ayley.

Their son Robert Ayley died in the Boeing 777 crash alongside 297 passengers and crew in July 2014.

The 29-year-old was heading home to Wellington after a month in Europe when he boarded the flight in Amsterdam bound for Kuala Lumpur.

He left behind a wife, Sharlene, and two sons who live in New Zealand.

"It was traumatising to know that my husband was on the other side of the world, lying in a morgue. It was surreal," Sharlene told the Herald in the months following Robert's death.

Meanwhile Robert's parents travelled to Britain to bring their son's body home.

This week they are "well aware" of evidence being given in a trial under way at a high-security court in the Netherlands, not far from where the Malaysia Airlines flight departed.

Families heard how steel fragments similar with those in a Buk missile warhead were found lodged in the bodies of the crew, passengers' luggage and wreckage, the BBC reported.

A number of telephone conversations ascribed to the four accused played during the hearing.

"They concern the role of the four accused in the events relating to the transport of the BUK-TELAR, the downing of flight MH17, and their mutual relationships," a court summary of facts said.

The prosecution and defence are scheduled to present their arguments on June 17 and relatives of the deceased will be given an opportunity in September to address the court.

Three Russians and a Ukrainian are accused of causing the crash and are suspected of being pro-Russian separatists.

All deny any involvement.

Gerry Menke, born in the Netherlands, and his wife Mary Menke, born in New Zealand, were also on board the flight. The couple lived in Victoria, Australia.