Sept 4 (Reuters) - New Zealand's SkyCity Entertainment on Monday said the country's Department of Internal Affairs (DIA) has applied to temporarily suspend the licence of its SkyCity Casino Management (SCML) unit, sending the casino operator's shares down 18.5%.

The application was made to the country's gambling commission to suspend the unit's casino operator's licence for a "range of 10 days", following a complaint made early last year by a former customer who gambled at the SkyCity Auckland casino from August 2017 until February 2021, SkyCity said.

Shares of SkyCity fell as much as NZ$1.900 by 0209 GMT, hitting their lowest level since April 8, 2020.

"The Secretary (of the DIA) states in the application that SCML did not comply with requirements in its SkyCity Auckland Host Responsibility Programme relating to detection of incidences of continuous play by the customer," SkyCity said in a statement.

SCML is SkyCity's licence holder for its casinos in Auckland, Hamilton and Queenstown regions in New Zealand.

The company did not comment further on the application, adding that it would fully comply with the DIA secretary in relation to the application and process.

The DIA in an emailed response to Reuters confirmed that it had recently completed an investigation into SkyCity's gambling harm-minimisation practices.

"The Secretary believes SkyCity has breached important harm-minimisation obligations including conditions of its licence and conditions of its Host Responsibility Programme relating to instances of long-play by its customers," said John Sneyd, general manager - regulatory services, DIA.

Last year, Australia's financial crime regulator launched civil proceedings against the casino operator's casino in Adelaide to crack down on the gambling industry.

(Reporting by Poonam Behura in Bengaluru, Additional reporting by Echha Jain; Editing by Paul Simao and Sherry Jacob-Phillips)