The increase will take Toyota’s total number of hybrid models to 20.
The Wall Street Journal reported that two would be luxury brand Lexus models and four would be Toyota vehicles.
Rival Nissan’s Leaf electric car is due in the US and Japan later this year, and Honda is to start selling electric cars in those markets in 2012.
As well as the new hybrid models, which run on petrol and electricity, Toyota will also unveil a fully electric version of its RAV4 sports utility vehicle later this year, the spokesman said.
The model, developed with its US partner Tesla, will be revealed at the Los Angeles auto show in late November. -BBC