Plans to strip down labour rights and make it easier for firms to sack under-performing staff have been labelled "complete nonsense" by Business Secretary Vince Cable.
The Liberal Democrat launched a direct attack on rival MPs who back the proposals, condemning the "ideological zealots who want to encourage British firms to fire at will".
It comes as venture capitalist Adrian Beecroft prepares to publish a far-reaching study recommending a raft of radical employment reforms.
Writing in The Sun, Mr Cable said: "Some people think that if labour rights were stripped down to the most basic minimum, employers would start hiring and the economy would soar again.
"This is complete nonsense. British workers are an asset, not just a cost for company bosses. That is why I am opposed to the ideological zealots who want to encourage British firms to fire at will."
Commissioned by Prime Minister David Cameron, the study is expected to call for firms to be given more flexibility to make redundancies, and an easing of equality rules to boost job creation.
Some of the plans are likely to be backed by Tories, with speculation the Prime Minister could be among those to show their support,
But Mr Cable said: "Those who want to shake up the law need to realise that the days in the 70s and 80s when the unions ruled the roost have long since gone.
"I talk to businesses every day and none of them tell me that their biggest obstacle to employment and growth is troublesome workers who they can't get rid of."
Conservative Party donor Mr Beecroft suggests a number of reforms in his 15-page report, including a reduction of the mandatory consultation period when a company is considering redundancy programmes.
He wants it brought down from 90 to 30 days - or just five if a company is in severe distress.
The report also recommends a cap on loss of earnings compensation for employees who make successful unfair dismissal claims and a removal of some equality laws.
Mr Cable's intervention comes as it emerged that he and and Labour leader Ed Miliband amid suggestions that tensions between their two parties are starting to improve.