An unidentified flying object that changed colour and shape was seen over Geelong on Sunday night.

A couple driving across the Barwon River bridge saw the mysterious display about 10pm.

"My partner and I saw what we thought to be an bright oblong object around 5-6m in diameter, ascending, whilst moving in erratic ways, changing colour and shape, from greens to blues to golds," the male witness said.

The display was said to have mirrored the balls of light seen zig-zagging across Corio Bay in April 2010, which was captured on video and shown on the Geelong Advertiser website.

There was later a claim the lights were remote-controlled aeroplanes.