A giant sinkhole has opened up on a suburban street in Coffs Harbour, as a severe warning for heavy rainfall and abnormally high tides is issued for Northern NSW residents.

Coffs Harbour City Council said a pipe under the pathway collapsed from the weight of the sodden soil.

It comes as intense weather continues to batter the east coast for the sixth day, with rainfall rates expected to ease slightly today as the trough weakens and extends south.

The Bureau of Meteorology kept severe weather warnings in place today for the Northern Rivers, Mid North Coast and Northern Tablelands in place as heavy rain, abnormally high tides and hazardous surf continue.

Authorities say the conditions have not been seen since Cyclone Debbie in 2017.

In Queensland, Bribie Island could be one storm away from being torn apart, after a week of cyclonic weather accelerated a decade-long erosion problem.

The northern end of Moreton Bay's crown jewel was holding on by mere tree roots after being ­battered for days by hazardous surf and high tides.

In NSW, an evacuation order is in place for Condong, Tumbulgum, Tygalah and surrounding areas along the Tweed River.

The SES says it's the final flood warning for the Tweed, with waters likely to begin receding today allowing for a clearer picture of the damage below.

A series of minor flood warnings have been issued for other rivers in the region, which is threatening thousands of homes.

Minor flooding has already been seen at Bellingen while flooding is expected on the McLeay River at Kempsey.

The rain system is then due to head south towards Sydney.

BOM meteorologist Shuang Wang said despite the low pressure system causing chaos moving south and "weakening" with milder 30km/h winds, ongoing rain, flooding and erosion was to be expected.

She said residents should brace for further wet conditions over the next three days.

"The low pressure system is tracking south and further inland, where it is weakening around the Mid North Coast … but there have still been very heavy falls," Ms Wang said.

"Wednesday to Friday, we will see more rainfall, potentially up to 100mm, and possibly severe thunderstorms."

The SES received 400 calls for help from locals since midnight on Monday mostly concerning leaking roofs and fallen trees, according to a spokesman, who said the organisation had received 1400 calls since the bad weather started last Thursday.

The state's north has been belted with near record-breaking rain since Sunday with the highest falls including Limpinwood with 547mm, Bellingen recording 533mm, Doon Doon copping 522mm and Boat Harbour seeing 516mm in the past three days.

Flood warnings remain in place on Wednesday for river systems in the Mid North Coast and Northern Rivers regions, including moderate to major flooding for the Bellinger and Kalang Rivers and moderate warnings for the Orara, Nambucca and Wilsons Rivers.

Minor to moderate warnings are in place for the Tweed, Richmond, Clarence, Macleay, Hastings, Manning and Gloucester rivers.

Current Flood Warnings for Wednesday:

Bellinger River: Moderate to major

Kalang River: Moderate to major

Orara River: Moderate

Nambucca River: Moderate

Wilsons River: Moderate

Tweed River: Minor to moderate

Hastings River: Minor

Richmond River: Minor

Clarence River: Minor

Macleay River: Minor

Manning and Gloucester Rivers: Minor

Originally published as Intense rain creates huge sinkhole in NSW street