North Korea has fired two short-range missiles into the sea off the east coast of the Korean peninsula, according to South Korea's defence ministry.

South Korea's Yonhap news agency reported the missiles likely flew about 500 kilometres after being launched off the North's east coast, adding they were believed to be Scud-C models.

South Korea's defence ministry has said the Scuds are normally fired using mobile launch pads which can be activated with minimal preparation.

The distance would mean the weapon could hit targets in South Korea and Japan.

It the second in a series of launches that Seoul has denounced as a calculated provocation.

Last week, North Korea fired four short-range missiles over the sea.

Reuters/AFP