A man who engaged in a 12-hour rooftop stand-off with police has formally been charged with the murder of his girlfriend.

June Oh Seo, 37, was arrested this month after spending more than 12 hours perched on the balcony roof of a high-rise apartment building in Chatswood, following the discovery of the body of his girlfriend Hee Kyung Choi in the laneway below.

Last week, Mr Seo was charged with a domestic violence-related assault occasioning actual bodily harm.

However, that charge was upgraded to include murder on Friday, when his matter was heard at Hornsby Local Court.