The nation's first federal small business commissioner will make advocacy for almost three million businesses his main focus.

The inaugural Small Business Commissioner, Mark Brennan, takes up the role today following his appointment last October.

Mr Brennan said he'll work alongside state and federal governments to make it easier for small businesses to access services such as business advisory and dispute resolution.

He said he sees the role as helping smaller firms by advocating for them to government and big business.

"No small business should fail through lack of information," Mr Brennan said in a statement.

"If we see small businesses and big business working together, you'll find the incidence of things like disputes will decrease."