Updated at 4.22pm:\nThe SAR Government and Guangdong authorities have been discussing an extension to Lowu check point hours, Chief Secretary Donald Tsang Yam-kuen said on Friday. The discussions have been examining changing the hours, which currently operate from 6.30am-11.30pm (Monday to Sunday), to include an extra half-hour on Saturday. This would mean the checkpoint would close at midnight on Saturdays. ''The plan depends on an efficient outcome. Scientific methods like Smartcard will also be introduced,'' Mr Tsang said. Mr Tsang said Lok Ma Chau Control Point would follow the same opening hours if the changes at Lowu proved satisfactory. It was hoped Lowu and Lok Ma Chau checkpoints would eventually run 24-hours a day, he said.