View of the fire incident site after a baby sitter intentionally set her master's house on fire, killing four people, at a high grade residence in Hangzhou city, east China's Zhejiang province, 22 June 2017.

The trial of a Hangzhou nanny accused of killing four people in an arson attack was suspended on Thursday when the defendant's lawyer walked out after failing to have the hearing moved to another court.

Mo Huanjing is alleged to have started a fire in a downtown apartment on June 22 that killed her employer, Zhu Xiaozhen, and three children, age 6, 8 and 11.

Her trial opened at 9 am at Hangzhou Intermediate People's Court. However, Mo's attorney Dang Linshan immediately raised an objection over the court's jurisdiction to hear the case.

"The police and prosecutors accepted the oral testimonies of only two of the 84 firefighters who took part in the rescue operation that day, which I feel is not impartial," Dang said.

"Moreover, I feel dissatisfied the court denied my request to invite 38 firefighters to serve as witnesses at this hearing during a pretrial meeting," he added.

While her lawyer addressed the judge, Mo, dressed in a black sports jacket, sat sobbing and trembling, flanked by two court officers.

Dang, an attorney with Guangdong Thai Law Firm, wrote on Sina Weibo on Dec 18 that he had applied to the Supreme People's Court to move Mo's hearing to a court outside Hangzhou, but had received no reply.

He gave five reasons for his application, including that the police had "intentionally not collected evidence thoroughly" and that prosecutors had "ignored the fact the police evidence was incomplete".

In court, Dang raised further objections and walked out of the hearing at 9:30 am.

The presiding judge said Dang's behavior was taken as a refusal to defend his client, and that Mo would be appointed a new attorney, Yangtze Evening News reported. The trial was adjourned to a later date.

According to police, Mo was addicted to online gambling and had stolen valuable objects from her employers as well as borrowed money on several occasions, China Central TV reported.