A watch and act alert was issued just after 7am today (Wednesday) for Lake Conjola following very heavy rainfall overnight. In Jervis Bay 218.8 millimetres was recorded to 7.30am today, with a further 194.2mm in Ulladulla.

Holiday Haven Lake Conjola manager Brad MacDougall took to social media at 6.30am on Wednesday, November 29 to provide an update from the edge of the lake.

"We've had a lot of rain since about 6pm yesterday [Tuesday], it hasn't stopped really," he said.

"The lake got up at about 2am over the banks and we were able to get everyone out.

"Most of the holiday vans north of the main road will probably be affected, there's still a lot of water there and it's still going up."

Mr MacDougall said not enough water is getting out from the lake.

"Unfortunately it doesn't look like it's getting out yet, hopefully, fingers crossed, there will be an excavator down here pretty soon," he said.

"Hopefully we can get rid of some of this water."

Shoalhaven City Council has not yet provided an update on the weather situation via its social media pages or website.

The SES said water levels on the lake have risen overnight due to severe weather, this has caused low lying areas of Lake Conjola to be impacted by floodwaters.

"This event may change quickly. We will monitor the situation and update our warnings if the situation changes," a spokesperson said.

With two flood rescues already conducted by the SES overnight, crews are urging people not to enter or drive into floodwaters.

"You really do not know what's under that water, even though it's a road you may have crossed earlier in the day," SES Chief Superintendent Dallas Burnes said.

Significant rainfall has been recorded in the 24 hours to 6.30am today (Wednesday), including: