The precious Vincent Van Gogh painting stolen then sensationally returned to a Dutch art sleuth in an Ikea bag has been scratched but should be reparable, its museum director told AFP Wednesday.

Thieves snatched the Van Gogh masterpiece "Parsonage Garden at Nuenen in Spring" in the middle of the night in 2020 while the painting was on loan to a museum near Amsterdam from its home at the Groninger Museum in the northern Netherlands.

The painting, worth up to six million euros ($6.45m), was then returned on Monday to Arthur Brand, known as the "Indiana Jones" of the art world for his work in researching and recovering stolen artworks.

Brand took possession of the painting bound in bubble wrap, a pillow case and stuffed in a blue Ikea bag, but the work still appears to have sustained some damage.

"It is damaged by scratches so it's not in a perfect state but it's restorable," Groninger Museum director Andreas Bluhm told AFP in an interview.

"When it's there in the IKEA bag, of course it was hot, so this is not ideal. It had already suffered for three and a half years," he said, adding: "But then bringing it in that same bag is quite safe because it's the least conspicuous way of moving it. Nobody would suspect anything."

The painting is now at the Van Gogh Museum in Amsterdam, where it is being examined, he said, adding that it could be some time before the work is available to the public.

"Even the restorer cannot tell you how long it will take. Probably months rather than weeks," he said.

What offers some hope for a successful restoration is that Van Gogh painted the work on paper glued to a thick wooden panel, rather than on canvas, so scratches should be superficial.

Bluhm said the time between the robbery and the recovery had been a rollercoaster of emotions. The piece had never before left his museum, so its theft came as a hammer blow.

"The painting is part of our museum's identity and our collective collection. So that hurt even more," he said.

Then came news last Thursday of a possible return, giving him sleepless nights.

"They said 'please come to Amsterdam to identify the painting'. I said 'OK, but I'll believe it when I see it'."

"You constantly keep on thinking about it but at the same time you don't want to hope too much because it could still fail," he said.

When the painting was finally identified, he went straight to the Van Gogh Museum in Amsterdam to give them an almighty surprise.

"They didn't even know I was coming. I called and said 'I'm coming, are you there? Can you open the door and let me in. I have something for you'."