News Limited has led the charge against the Government's plan and it will be among the big media players appearing at the inquiry.
Communications Minister Stephen Conroy says his plan supports media diversity and improves regulation, but media groups call it unacceptable government intervention.
The Senate committee has until June to consider the six bills, but Senator Conroy insists both houses of parliament must deal with them this week.
The short timeframe seems to play against the Government, with independents indicating they want more time to work with the bills.
Senator Conroy has refused to negotiate on the reforms and says they will be scrapped if they are not accepted in their current form.
He told Insiders yesterday the bills will not go to a vote in the Lower House if they do not have support.
"Five-and-a-half years this has been on the agenda. To suggest that this suddenly has come out of nowhere - when I've been campaigning for five-and-a-half years on the public interest test - is a nonsense," he said.
"The Parliament knows it's got a choice: if you want to ensure there is no further concentration in the media in this country, one of the already most concentrated, you vote for the bill.
"If you want to ensure that the Press Council upholds its own standards, you vote for the bill. Those are two very simple problems."
Opposition communications spokesman Malcolm Turnbull has described the process as a "shocking shambles".
The committee will consider six bills, including one to halve the annual licence fees television networks pay, which appears most likely to pass.
However, the amount of support for other bills, which include establishing a public interest advocate and encouraging diversity, is uncertain.
The Coalition has already declared it will oppose the legislation, so the votes of crossbench MPs will be crucial.
Former Labor MP Craig Thomson says he will vote against the bills, but the Coalition says they will counter his vote by withdrawing one of their own MPs.