The government is trying to force through a plan for police to keep innocent people's DNA profiles for up to 12 years, without seeking approval through a vote in the House of Commons.
The Conservatives and Liberal Democrats claim the government is seeking to make controversial changes to the national DNA database via secondary legislation known as a "statutory instrument".
Unlike primary legislation, statutory instruments are not debated in the Commons.
"It is not good enough for ministers to circumnavigate parliamentary process just because they are running scared of another defeat," Chris Huhne, the Lib Dems' home affairs spokesman told The Observer.
"With this administration's history of legislative diarrhoea, there should be room for the discussion of something so important on the floor of the House."
Earlier this month the government announced the plan to keep innocent people on the DNA database despite a landmark ruling by the European Court of Human Rights last year saying they should be removed.
The latest proposal says those arrested but not convicted of serious violent or sexual crimes will be kept on the database for 12 years while those arrested but not convicted of all other crimes will be kept on the database for six years.
But opposition parties and civil liberty groups have united to condemn the plans that are being steered through parliament while MPs and the public are distracted by the ongoing expenses scandals.
A statutory instrument has to be discussed only by a specialist committee set up by the government which meets for 90 minutes and is usually made up of 16 MPs and a chairman.
A review of parliamentary procedure for the Conservatives known as the Norton Commission recommended that the use of statutory instruments as a tool for introducing legislation be stopped.