Dutch prosecutors said on Tuesday they have identified many "persons of interest" in their probe into the shooting down of flight MH17 over Ukraine, but no definite suspects, Le Figaro edition website reported.

"We have a large group of people that we're at this stage branding 'persons of interest' in whom we have an above average interest," Dutch chief prosecutor Fred Westerbeke told at a press briefing in Rotterdam.

"But we've not yet taken the formal step of making them suspects," he told journalists, almost a year after the Malaysia Airlines flight was downed over war-torn Ukraine, killing all 298 on board, the majority of them Dutch.

The Netherlands has been tasked with leading the investigation into the cause of the disaster and identifying the victims of the July 17, 2014 crash.

It is also in charge of the criminal prosecution of those responsible.

Westerbeke said although "great steps" were being made in the criminal probe to find those responsible, a dossier to take to trial would not be ready "at least before the end of the year."