The Bimberi Wilderness, a 29,000 hectare area of the national park, will be closed until the end of March.

It's the first time the area will be closed to visitors for an extended period of time since the 2002-03 summer, when the Canberra bushfires ravaged the ACT.

ACT conservator of flora and fauna, Ian Walker, said the decision to close the national park was made to protect the community.

"This is about being precautionary. We know that fuel moisture levels are low and temperatures are increasing and there's no sight of rain or cooler conditions coming," Mr Walker said.

"It's a remote area of the national park and it's rugged and access is relatively limited, but we want to make it clear to people it's closed because of the increased fire risk across the ACT and across the country."

The national park closure will affect the ACT section of the Australian Alps walking track, along with Pryors Hut, Mount Gingera, Mount Bimberi, Cotter Hut and Upper Cotter.

Public access will be closed at the Ginini car park on Mount Franklin Road, Stockyard Spur, Smokers Trail and Cotter Hut Road.

The closure will be enforced with road blocks and signage across roads leading into the national park.

Mr Walker said further closures to other areas of the national park were on the cards if conditions continued to deteriorate.

"It is a consideration going forward, and if we don't get more rain, we will consider making further closures," he said.

"The park is already closed on total fire ban days and we'll explore further closures of Namadgi if needed."

National parks staff say it has been some of the driest conditions they have seen in years.

Rivers in the national park completely dried out two weeks ago.

The Bureau of Meteorology said it was expected there wouldn't be any significant rainfall in the area until at least February.

Peter Cotsell, operations manager of ACT southern parks and reserves, said national parks staff would be checking issued permits and making sure all visitors were out of Namadgi.

"We'll be checking records and making sure," he said.

"We'll go into the wilderness areas and access areas to make sure people are not in the park, and we have good records of who is in there.

"It's incredibly dry at the moment and the rate that a fire would spread under these conditions would be rapid."

National parks staff said they weren't concerned about the effects the closure would have on visitor numbers.

"Visitation to the park and to the alpine environment is good during the summer," Mr Walker said.

"But I would encourage the community to think about their visit to any national park generally, as we have a heightened fire risk not just in the ACT but across the country."