But Liberal MPs insist the proposed changes are nothing to be concerned about.
The government plans to cut the number of Senate committees from 16 to 10 and says only coalition senators would chair them.
Labor's treasury spokesman, Wayne Swan, says the changes are a clear abuse of the government's power in the Senate.
And the opposition's industrial relations spokesman, Stephen Smith says the government is trying to undermine the power of the Senate to avoid public scrutiny.
The Labor leader, Kim Beazley, agrees with his colleagues.
“Like all instruments of accountability in the country, this government is trashing it. This is because the government believes the more people know about it the less likely they are to support it. Now it's a sound judgement on their part, but it's an evil act,” said Mr Beazley.