Emergency Management Minister Murray Watt said a flood levee in Singleton was expected to hold despite intense rain in recent days, with the helicopter stationed primarily for night-time search and rescue.

Three ADF helicopters are mobilised, while no additional troops are currently headed to NSW to assist with the emergency situation.

"As I understand it, (no helicopters) were required last night but there is now one that's stationed in the Hunter and available for use," Senator Watt told Sky News.

"We've got 250 troops that have been activated and made available to the NSW government, basically to help supplement the SES but we have indicated repeatedly ... if they feel they need more assistance, then we'd obviously consider that."

Federal government disaster payments of $1000 go online from 2pm on Thursday, with Senator Watt expecting a barrage of applications given some 40,000 people are currently subject to evacuation orders.

He denied the government was not doing enough to support people who had felt huge impacts such as losing a business.

"(The $1000 payment) really is intended as an immediate injection of funds to people who, for instance, need to restock their fridge and they've lost all their clothes - some sort of an immediate payment so that people can actually put clothes on their back and food on their table," he said.

"But there will be a wider range of payments available to people such as small businesses and farmers who have suffered damage, and those amounts are much more extensive than the $1000."

Taking a long-term view, Senator Watt acknowledged preparing for future events and flood-proofing vulnerable regions would need to become a priority.

"We're certainly prepared to talk about those kinds of things because while they cost a lot of money to do, we're also spending a huge amount of money every time we have to repair the infrastructure in homes and make these payments," he said.

Australian Associated Press