The gates at Kohlhagen's travelling stock reserve (TSR), on the Old Narrandera Road, have been padlocked shut - one of three irresponsible disposals under investigation by Riverina Local Land Services (LLS).

In the latest incident, authorities were alerted to multiple dumps beside the Wagga-Holbrook Road about 17km south of Wagga at the weekend.

Two large piles of household material - including lounge room furniture, mattresses, carpet and timber - were disposed of at Plum Pudding Reserve, near Coloboralli Creek.

Both have been dumped just a couple of metres off the road and about 250 metres apart.

Riverina LLS acting manager of land services Mark Leary said samples of the material had been sent to a Melbourne laboratory for analysis and the outcome would determine the presence of asbestos.

Mr Leary described the area as a hot spot for illegal dumping, which was a "huge concern" irrespective of location.

"This is something that happens on a regular basis," Mr Leary said.

"The chances of finding the owner of the waste ... is next to zero.

"It's a sad situation that people don't utilise the facilities that are there (to dispose the material correctly)."

Mr Leary said an initial inspection of the Kohlhagen's TSR rubbish indicated a presence of asbestos was highly likely but the extent of contamination at the Plum Pudding reserve was yet to be determined.

"The clean-up costs skyrocket as soon as it's asbestos," he said.

The latest dumps come just weeks after new compliance signs and surveillance cameras were rolled out at public reserves to combat illegal activity - a joint initiative by Riverina LLS, Wagga City Council and Crown Lands.

The third dump under investigation is in the Tumut area.