The Senate today voted down the use of the word 'arson'.

Australian Greens Leader Bob Brown's amendment to a bushfire inquiry proposed by Senator Bill Heffernan to the Agriculture Committee was altered from 'arson' to 'accidental, natural and deliberate' causes.

When Senator Brown moved an amendment to insist on the word 'arson', Government and Coalition Senators voted it down.

"I call arson arson," Senator Brown said.

"It is time we faced the reality of arson and investigated the reasons for it and its remedies," he added.