A 16-year-old youth has appeared in court charged with bestiality after allegedly having sex with a donkey in Sumner yesterday.

Police arrested the youth after a member of public phoned them after seeing what was happening from their house above the Sumnervale Reserve about 2pm.

He appeared in the Christchurch Youth Court this morning and was remanded until May 4.

The youth had allegedly taken the four-year-old donkey into the middle of the reserve, which is about the size of a football field.

The member of public lived in a house above the field and took photos while phoning police.

Other young people were at the reserve at the time, but appeared not to have seen what happened, police said.

Police said the youth could offer no explanation for his actions.

The youth was held in custody overnight and was scheduled to appear in court today.

Bestiality carries a maximum jail sentence of seven years.

Police said to have someone so young charged with bestiality was rare.

The youth did not live in the Sumner area, police said.