The three-year-old's finger became firmly wedged in the plughole about 6pm on Thursday, and he remained stuck there for five-and-a-half hours.

Firefighters said the particular design of the boy's Kew East home meant that the operation was a more difficult one than usual.

The toddler, who watched videos during the protracted operation, eventually had his finger separated from the plughole in Box Hill Hospital.

MFB Commander Brian Rogasch praised the boy for remaining calm and patient throughout the long episode and rewarded him with an MFB trauma teddy.

- with AAP