Heavy rain is causing surface flooding on Christchurch roads, with some homes near rivers swamped

A 'red warning' for heavy rain remains across Canterbury as significant weather unfolds and is due to continue until tomorrow.

Fire and Emergency say homes and streets near the Heathcote River are waking up to flooding and roads underwater.

Civil Defence is on standby, with council and emergency services due to meet later this morning.

A strong wind warning is in place for Westland south of Hokitika and Fiordland -- and a heavy rain watch is in place for North Otago and Dunedin.