More than 25 bushfires are merging in eastern Victoria and will create an inferno of half a million hectares, authorities warn.

Fire Services Commissioner Craig Lapsley said lightning strikes started a series of fires in East Gippsland which were uniting into a single blaze that could soon cover an area of more than 500,000ha.

“That fire has the potential to burn significant areas over the next couple of days,” he told reporters on Friday.

An emergency warning was issued for Club Terrace, near Mallacoota, on Friday afternoon, with an immediate threat to the town.

Mr Lapsley said the fire would likely take more than a week to be controlled.

Emergency Services Minister Kim Wells said efforts were being made to protect vital electricity transmission assets in the area.

In West Gippsland, emergency warnings were issued for Glenaladale, Iguana Creek, Fernbank and The Fingerboards, over a fast-moving, out-of-control bushfire travelling in a south and easterly direction.