A conservation charity on Tuesday accused an American tourist of killing a much-loved Zimbabwean lion called "Cecil" on a hunt using a bow and arrow, adding that the animal had taken 40 hours to die.

The lion, which was a popular attraction among visitors to the Hwange National Park, was tempted outside the park using bait and then shot earlier this month.

The Zimbabwe Conservation Task Force charity named the alleged trophy hunter as Walter Palmer from Minnesota, saying he had paid $50,000 for the hunt.

The charity said Palmer and professional hunter Theo Bronkhorst had gone hunting at night and tied a dead animal to their vehicle to lure Cecil, who was aged about 13, out of the national park.

"Palmer shot Cecil with a bow and arrow but this shot didn't kill him. They tracked him down and found him 40 hours later when they shot him with a gun," the charity alleged.

It added that the hunters then found that the dead lion was wearing a tracking collar, which they unsuccessfully tried to hide.

"Cecil was skinned and beheaded. We don't know the whereabouts of the head. Walter Palmer apparently paid $50,000 for the kill and we assume Theo Bronkhorst received this money," the charity alleged.

Bronkhorst and the local landowner Honest Ndlovu will appear in court on Wednesday to face poaching charges, the Zimbabwean Parks Authority said Tuesday.

"Both the professional hunter and land owner had no permit or quota to justify the offtake of the lion and therefore are liable for the illegal hunt," it said in a statement.

The statement made no mention of Palmer, but added that Bronkhorst's son Zane was also wanted for questioning.

Zimbabwe Conservation Task Force said Cecil's cubs were likely to be killed by the lion that took over in the group's hierarchy.

Cecil was described by safari operators as an "iconic" animal, who was recognised by many visitors to Hwange for his distinctive black mane.

The court hearing is due to be held in Victoria Falls on Wednesday.

The safari operators association was due to give a press conference later Tuesday.