Severe rain and hail storms were battering parts of southern NSW on Sunday afternoon. Hail fell at Marulan, in the state's southern tablelands, a caller to Macquarie Radio said.

"It's unbelievable chaos down here the rain is so heavy that the hail was just incredible and it's hailed for a good 20 minutes," the caller, Judy, said. "We were under a tree and we had branches coming off as well. Some of the hail was just pea size but occasionally I'd say that they were golf-ball size."

The Bureau of Meteorology issued a severe thunderstorm warning at about 4pm (AEDT) Sunday with the forecast of large hailstones falling for several hours in several locations.

The storms were heading north and were expected to reach Moss Vale and Bowral in the Southern Highlands.