AUTHORITIES are now predicting the Clarence River will reach 7.1m by tomorrow morning as heavy rain continues to drench the catchment.
The Bureau of Meteorology issued a revised flood warning at 1pm, but was still not predicting a peak for the Grafton waterway because of uncertainty over how much more rain will fall.
In its 9am update the BoM had been predicting a river height of 6m by Tuesday morning.
At Ulmarra the river is tipped to reach 5.6m by late Tuesday morning with major flooding, while in Maclean it is expected to reach 3m by Tuesday afternoon with major flooding.
An average of 187 millimetres of rain has fallen during the past 54 hours to noon today in the catchment.
Further heavy rain is forecast for Monday.
The next update will be issued at 3pm.
The Pacific Highway remains closed in both directions just south of Grafton due to flooding.
Motorists are advised they can still get through as there is a diversion in place via Clarenza that is also suitable for heavy vehicles and B-Doubles 19m and under. Restricted vehicles are advised to use the New England Hwy, Bruxner Hiwy and the Summerland Way.
Current closures due to flooding:
Meanwhile, the Pacific Hwy remains closed in both directions just south of Grafton due to flooding. There is a diversion is place via Clarenza.
Tweed Valley Way is closed near Murwillimbah.
Bangalow Road is closed between Lismore and Bangalow.
Gwydir Highway is closed at the Gibraltar Ranges. It is expected to remain closed till at least this evening.
Ulmara Ferry is out of service.
Lawrence Ferry is out of service.
The situation is changing quickly so motorists are advised to avoid travel if possible.
1900 cut off by rising floodwaters
COMMUNITIES are bracing themselves as ex-tropical cyclone Oswald crosses northern New South Wales, where more than 1900 people have been cut off by rising floodwaters and 4500 homes have been blacked out.
Wind gusts have been up to 50 knots.
There were 10 rescues in the Richmond-Tweed SES area overnight, and a man rescued from the roof of his car Monday morning after attempting to drive through a flooded creek at Murwillumbah.
The Pacific Highway has been cut by floodwaters just south of Grafton.
The New South Wales State Emergency Service (SES) has had a busy night, with more than 720 calls for help.
Coffs Harbour SES says crews are preparing for peak gusts of 140 km/h and storms later today.
Heavy rain is expected throughout the morning, combined with severe winds and very large swells.
The SES's Bill Roffey said the service's focus was likely to turn to storm jobs around lunch time, with strong wind gusts expected after the rain.
SES Commissioner Murray Kear advises travellers to delay for the next 24 hours, but if road travel is a must, to be very careful and follow the directions of emergency services.
The towns of Thora, Bellingen, Murwillumbah and Mullumbimby have minor flooding.
Flood warnings are current for the Wilson, Richmond, Tweed, Clarence, Bellinger, Brunswick and Hastings rivers.
The Tweed River at Murwillumbah was peaking near 4.2 metres at 7.40am, causing moderate flooding after 380 millimetres of rain fell in 48 hours.
Flooding is expected to be moderate for the Wilson and Richmond rivers after the catchment received an average of 260mm in 48 hours.
The weather bureau says flood peak predictions are generally not yet possible because of uncertainty over further rain.
Some predicted river heights and flows are as follows:
Lismore - 8 metres about 9pm Monday, evening with moderate flooding.
Wiangaree - peaking near 11 metres with minor flooding.
Kyogle - moderate flood level (14.4 metres) around noon on Monday.
Casino - minor flood level (9.2m at the Road Bridge gauge or 12 metres on
the automatic downstream gauge) about midnight Monday.
Coraki - 4.8 metres on Tuesday evening with minor flooding.
Bungawalbin Junction - 4.2 metres on Tuesday evening with minor flooding.