Tropical moisture extending south from the Coral Sea will combine with an upper trough to produce extensive thunderstorm activity this afternoon and evening.

The Bureau of Meteorology's alert issued at 3pm is for severe thunderstorms, likely to produce heavy rainfall that may lead to flash flooding over the next several hours in the North East.

Locations which may be affected include Shepparton, Seymour, Wodonga, Wangaratta, Bright and Falls Creek.

The NSW SES Albury Unit has packed more than 80 sandbags for residents who may require them.

Commander Curtis Kishere said sandbags had been collected for four properties.

"We're trying to help people be storm-ready; we are expecting 50 to 100 millimetres tonight and tomorrow that may lead to flash flooding," he said.

"We can never predict how much damage will be done."

It comes after storms passed over the Border and North East today, causing trees to come down and reports of building damage at Rutherglen.

A spokesman for SES Victoria said there had been 21 requests for assistance in the 24 hours to 3pm.

"Twenty of those have now been cleared, and they mostly relate to downed trees," he said.

"Requests for assistance were spread across the region."

North of the border, a lightning strike sparked a fire at a home.

The SES spokesman said rain and storms were also forecast on Thursday and Friday.

"There's going to be some thunderstorm activity over the next couple of days; the activity will be widespread but there will be cells within that which are relatively severe," he said.

IN OTHER NEWS:

"Drive to conditions and download the Vic Emergency app to set a watch zone and get local information."