Zimbabwe has abandoned its bid to press criminal charges against a US dentist who killed Cecil the lion, saying his papers “were in order” and that he did not know he was committing any offence.

The black-maned lion was shot dead with a powerful bow and arrow in July by US trophy hunter Walter Palmer in a hunt that provoked worldwide outrage.

Palmer paid $US55,000 ($A75,095.58) to shoot the lion on an expedition led by professional Zimbabwean hunter Theo Bronkhorst.

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The hunt provoked a storm of criticism after it emerged that Cecil was a well-known attraction among visitors to the Hwange National Park and was wearing a tracking collar as part of an Oxford University research project.

But a Zimbabwean government minister on Monday said they would not pursue any legal proceedings against Palmer.

Environment Minister Oppah Muchinguri told reporters Palmer’s “papers were in order” when he came to Zimbabwe.

“We are now going to review how we issue hunting quotas,” Muchinguri said.

“The documents were there … The problem now remains internal.”

The dentist was welcome to return to Zimbabwe but “not for hunting”, she added.

Muchinguri had previously called for Palmer to be extradited from the US.

Palmer was hounded on social media over the killing and, after demonstrations outside his dental practice in Minnesota, went into hiding for weeks.

He later apologised for killing Cecil, a 13-year-old male renowned for his distinctive black mane.

Palmer said he believed it was a legal hunt and appeared to blame Bronkhorst for misleading him.

Muchinguri said Honest Ndlovu, the local landowner, did not have a hunting quota for a lion but that the rural district council covering the land did have one.

Bronkhorst has been charged with “failing to prevent an illegal hunt” and is due back in court on Thursday when the judge is due to decide on his application to have the case against him thrown out.