A landowner on the New South Wales southern tablelands says parts of the region could become desert-like unless urgent action is taken to prevent the spread of a noxious weed.

John Campbell owns a farm at Taralga in the Upper Lachlan Shire and said there had been an "alarming" expansion of serrated tussock, which is an introduced species native to South America.

The weed is nationally recognised in Australia because it poses a significant threat to pastures, particularly during dry conditions, and is difficult for stock to digest.

Mr Campbell said a rise in absentee landowners and lack of awareness had accelerated the spread of serrated tussock.

He has written to the Upper Lachlan Shire Council urging for immediate action, and said authorities needed greater powers to enforce landowners' management of the weed.

"It will absolutely turn into a desert if we don't get more aggressive in the way we tackle this weed," Mr Campbell said.

"The problem we have in this particular area now is we have a lot of absentee, small landholders who aren't doing anything about their tussock problem.

"They just see it as a piece of grass and don't realise that if you don't get rid of it, your whole property will end up covered in the stuff and a lot of the small farmers that come in and don't stay there long."

Mr Campbell said while weed management was an individual landholder's responsibility, he believed authorities were "powerless" as they could not effectively enforce the issue.

Need for more education

The Upper Lachlan Shire Council says serrated tussock remains the "number one priority" weed on the southern tablelands.

The Council's noxious weeds manager Paul Brown said despite efforts to make people aware of their responsibilities, a high number of absentee landowners made it difficult.

Mr Brown said more public education was needed to ensure effective management of serrated tussock.

"Because the number of absentee landowners is increasing, it can be challenging to introduce the programs that are needed to provide that education to get to everyone to make them understand the problems associated with this weed," Mr Brown said.

"Certainly all landowners need to be aware of their responsibility to control serrated tussock and our council is endeavouring to make people aware that it's in their interest to control it, because their investment in land can be reduced if they don't control it."

Mr Brown said a new biosecurity framework being rolled out across New South Wales would hopefully address many issues around noxious weeds.

"Hopefully the State Government will assist with education programs that councils can provide to landowners," Mr Brown said.

The recently developed New South Wales Biosecurity Act is expected to come into effect in 2017 and will address issues of weed management and plant biosecurity.