The New South Wales Government is being asked to expand kangaroo harvesting in the state's west to curb ballooning numbers of the animal.

Farmers and councils want a review of current guidelines, which require a landowner to apply for a licence specifying how many of each species can be shot.

Kangaroo management zones cover most of New South Wales and apply to red, eastern grey and western grey kangaroos, as well as wallaroos.

A letter has been written to the Primary Industries Minister Niall Blair, calling for a review of kangaroo management practices to increase quotas.

Currently, a landholder must apply for a licence, which outlines how many of a roo species can be shot.

Quotas of between 15 and 17 per cent are in force to keep populations sustainable.

But Western Division Councils president Leigh Byron said this should be expanded.

"If we could get that increased or more shooters are allowed out there it would be a big improvement," Cr Byron said.

"If all of a sudden you're only shooting them on Crown Land, where are they going to go? They're going to go onto the farmers' property and just destroy their crops."

Cr Byron said the large number of kangaroos was devastating crops and pastures.

"It has gotten it a lot worse in the last year or so," Cr Byron said.

"They're just as thick as flies in some places. A huge impact.

"They flatten the crop, they eat the crop, they flatten fences down. It's just a real problem."

Letter from young girl calls for action on kangaroos

Part of the push has been sparked by a letter sent by a young girl living on a station near Euston in the state's south-west.

The letter said kangaroo number on her family's property was worrying.

"I counted 80 kangaroos in the top right corner of a 200-hectare paddock," the letter read.

"People don't realise what damage they do to farmer's production across Australia. If we can't grow what will happen to the rest of the world?

"How are farmers supposed to provide to the country and the rest of the world if kangaroo population prevents us from harvesting a crop?

"I may not be a the smartest when it comes to maths or English, but what I do know is those people who think that Kangaroos are almost extinct, boy they are wrong!"