A Labor MP has offered the federal treasurer a free iTunes card if he can improve crowd-funding measures for Australian businesses before the end of the year.

Parliament's lower house on Wednesday passed legislation that will allow unlisted public companies with less than $25 million in assets and turnovers to raise up to $5 million in funds a year.

The opposition's start-ups spokesman Ed Husic labelled it a "half-baked effort", telling MPs it would only open the door for a small number of businesses.

It shouldn't be restricted to unlisted public companies and that privately-held firms should also be included, he said.

Treasurer Scott Morrison flagged a subsequent bill will be introduced to extend it to proprietary companies in the near future.

But Mr Husic believes it will take so long for that to come through, he bet him an iTunes card that it won't be in place by the end of 2017.

"Why is it that we are doing this in a two-step way where, instead of just doing this all at once, knowing that it's going to take time for the system to come into place anyway?" he said.

Mr Morrison said it had already been too long and accused the opposition of frustrating the passage of the measures last year.

"We need to do it now, and there'll be other measures that will follow that this government will introduce."