Malcolm Turnbull's infrastructure pitch to Victoria has run into serious strife just days after it was announced, with a state minister dismissing a key federal demand as "birdbrained".

Roads Minister Luke Donnellan​ has confirmed Victoria will not be yielding to one of Mr Turnbull's main conditions attached to $1.5 billion of Commonwealth infrastructure funding outlined late last week.

The Monash upgrade is seen as crucial by Liberal strategists

In addition to matching the $1.5 billion of federal cash dollar for dollar, Mr Turnbull has demanded the Andrews government separate an existing $400 million project to upgrade Monash from its $5.5 billion Western Distributor plan.

The Monash upgrade, along with the offer of $3 billion to the first Victorian government prepared to build the East West Link, is seen as crucial by Liberal strategists, with several key marginal seats in Melbourne's south-east.