Yarra liquid spill no risk: fire officials

An unknown liquid which spilled into Melbourne's Yarra River is not a fire risk, authorities say.

The Environment Protection Authority is investigating the liquid which spilled between Spencer Street and Kings Way on Wednesday afternoon.

A Metropolitan Fire Brigade spokesman said the liquid was believed to be an organic substance.

"The EPA's advice to us was to disperse it, drive through it in boats and spread it with the propellers," the spokesman said.