The communities of Condobolin, Euabalong, Euabalong West and Lake Cargelligo are on further alert going into the weekend with the Lachlan River expected to peak at levels higher than ever recorded.

Condobolin  SES Unit Commander, Susan Bennett says the predicted river levels do not include the rainfall forecast for the weekend.

"The predictions at the moment are higher than ever recorded," she said. "We are hoping that won't happen."

"The Bureau is also predicting up to 4 inches (around 100millimetres) of rain which would also impact us."

The SES and other agencies use historical measurements, meticulously kept since 1952, to predict impacts on local infrastructure and the local community including which streets and facilities can be expected to be inundated at certain heights.

However, river levels above the 1952 peak bring a new level of uncertainty.

"We don't have intelligence on 7.4 metres or higher," Ms Bennett said. "We know what happens at 7.36metres but even 4 centimetres higher over the area that is already affected is significantly higher."

A Watch & Act alert is in place for the entire area along the Lachlan.

Ms Bennett says the river is expected to reach 8.5 metres at Euabalong with the levee good for 9 metres.

"There will be consequences for Lake Cargelligo which is already sitting at 177%," she said. "Murrin Bridge won't be affected unless the river reaches 8.5 metres."

The levee at Euabalong is expected to withstand the predicted river height however the township will be cut off and storm drains will need to be blocked.

"There are just so many things coming into play," Ms Bennett said. "At this point, until it comes through Condobolin we don't know what will happen downstream."

"It is higher already than 2016 and because the ground is sodden at 7.1metres this week the water is higher and has spread to places we haven't seen it before and affecting people who haven't been affected before at this level."

Watch this video from the SES.

Most roads remain closed although there is still access to Parkes for some vehicle types and the road to Tottenham is open, however roads north, east and west from Tottenham are closed.

The small community of Derriwong is preparing to evacuate due to questions over whether their levee will continue to hold.

"We've been out to Derriwong, doorknocking to have people ready if it does happen," Ms Bennett said. "We don't evacuate unless it's absolutely necessary."

The Australian Defence Force spent 10 days in the Condobolin area. They helped shore up the Derriwong levee. IMAGE: Condobolin SES

The SES have been continuously occupied with supplying isolated homesteads and smaller communities like Euabalong, Euabalong West and Mt Hope.

"We're doing everything we can to get there and keep them supplied," Ms Bennett said.

With only small SES Units at Condobolin and Lake Cargelligo, Ms Bennett say they are heavily reliant on out-of-area assistance.

"We have a skeleton crew and its very hard to get out of area assistance crews to Condobolin when so many areas in the state are flooded," she said.

"When they do get here we're very grateful.

"Our community is now starting to respond because they realise we're all in this together."

"We get fantastic support from our brother and sister agencies the Rural Fire Service, Police, Maritime Services and Council."

Despite having "very good rescue capabilities" Ms Bennett says undue pressure has been placed on the already stretched crews when people ignore road closed signs or take other risks that then require them to be rescued. She hopes this is beginning to change.

"We've had farmers decided to get out because they can't fight the water anymore," she said. "About half a dozen houses have already been inundated and there are possibly up to fifty at risk."

"People are realising its not business as usual, it's be prepared, make calls and think ahead."

Ignoring road closed signs can get you into trouble such as this truck on Murie Road, Condobolin earlier this week. IMAGE Condobolin SES.

Based on predictions from the Bureau of Meteorology, the following areas may be impacted by

flooding:

• Low lying areas may be impacted by inundation
• The Booberoi Road (Euabalong – Condobolin) can be impacted by water.
• Forbes-Condobolin Road may be impacted in multiple locations.
• Rural land inundation along North Forbes Road, Lachlan Valley and Kiacatoo Road.
• Lachlan Valley Way between Euabalong and Lake Cargelligo can be impacted by water.
• Condobolin - Diggers Avenue may see water through causeway
• Condobolin - The Gipps way causeway may flood where access to West Wyalong will be
• cut.
• The older part of Riverview Caravan Park may become isolated
• Dwelling adjacent to Lachlan River on Diggers Avenue starts to flood
• Lachlan Street between William Street and Denison Street can be impacted by water
• Rural properties along North Forbes Road and Grassmere Road may become isolated
• Further rural properties isolations along Wiatoah Lane, Kiacatoo Road, North Forbes
• Road and Lachlan Valley Way to the east and west of Condobolin may occur

For emergency help in floods and storms, call the NSW State Emergency Service on 132 500.

In life threatening situations, call Triple Zero (000) immediately.