Insurgency leader Andrei Purgin said about 40 per cent of the plane's charred parts were left behind by international investigators and recovery teams.
Kiev and its Western allies accuse the militants of accidentally shooting down the Boeing 777 liner after mistaking it for a Ukrainian jet.
All 298 passengers and crew who boarded the Kuala Lumpur-bound flight MH17 in Amsterdam were killed.
The rebels and Moscow accuse the Ukrainian military of shooting the jet out of the sky in a seeming bid to damage the separatists fighters and Russia's global reputation.
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The investigators "assured us they do not need those parts," he was quoted as saying by the rebels' official news site.
International teams have collected body remains and plane fragments to help a Dutch-led inquiry into what caused the airliner to go down last July.
The Netherlands is also in charge of the criminal prosecution of those responsible.
The Dutch Safety Board said in an initial report last year that the plane had been hit by numerous "high-energy objects".
A final report is expected within months.