THE Sunshine Coast is bracing for its own extreme weather event as the remnants of ex-Tropical Cyclone Debbie zero in on the region bringing with it heavy rain, gale force winds and powerful seas.

Heavy rain to 400mm in places is expected to begin to fall this afternoon and continue into the evening with the 10.04pm high tide likely to test low lying coastal areas.

Sunshine Coast Council chief engineer and Local Disaster Management Centre coordinator Andrew Ryan said contractors with heavy equipment were on standby to, if necessary, buffer coastal zones eroded by seas which will reach up to four metres in height.

Yesterday home owners in low-lying areas began pouring into SES depots to collect sand bags to buffer homes which historically have been vulnerable to flooding.

Maroochydore SES leader Danielle Pratt said 500 bags had been collected from the Buderim depot alone with the group also responding to 16 call outs to sand bag properties for elderly and frail residents.

Mr Ryan said problematic storm water drainage systems at Cotton Tree would struggle to clear water around the high tide and may result in flooding of low-lying areas.

With falls of up to 400mm in the hinterland a swollen Maroochy River may also see Bradman Avenue at Maroochydore cut along with hinterland roads throughout the catchment.

Mr Ryan said the expected significant swell would test beaches that have gone for the past two to three years without large scale activity.

He said the Local Disaster Management Centre in Nambour was likely to be fully activated this morning ahead of what is expected to be a busy night.

A Flood Watch has been issued for the Mary, Noosa, Maroochy and Mooloolah rivers and their tributaries as heavy rain from Cyclone Debbie moves into the south east corner.

Latest forecasts are for 37-46kph north north easterly winds on Thursday to increase to 74 kph in the evening driving seas of 1.5-2.5metres which are expected to increase to 2.5 to 4m by midday.

A swell of one metre from the north east would also increase to between 1-2m in the evening.

Friday would also see rough conditions off shore with north north easterly winds at 46 to 74 kph which would swing south west through the day but remain at 46-65 kph in strength.

Chaotic seas of two to four metres would be driven by a north north easterly swell at 2-4 metres decreasing to 1.5-2.5 metres and a second swell of 0.5 metres from the south increasing to 2-3 metres.

Rain forecasts are dependent on the eventual track of the low pressure system that remains as the cyclone's remnant, however wide spread rain averaging 150mm is expected across the catchment with some areas likely to experience up to 400mm in a day.

The Bureau of Meteorology says the Flood Watch means that people living or working along rivers and creeks should monitor the latest weather forecasts and warnings and be ready to move to higher ground should flooding develop.