Labour's approach to the war on terror is destroying the British way of life, Liberal Democrat MP Lembit Ípik claims.
Liberal voices: Lembit Ípik MP and Mike German AM at the conference
He said Labour's "hopeless prejudice" had led to laws which could be a "recruiting sergeant for terrorism".
The Welsh Lib Dem leader also told supporters in Cardiff the only time the Welsh assembly had been stable was when his party shared power with Labour.
He ended the party conference by predicting Lib Dems would raise their total of two Welsh MPs at the election.
Mr Ípik was among the MPs - including party leader Charles Kennedy - who missed the start of the conference because of the lengthy parliamentary debate on the Prevention of Terrorism Act, which was finally passed on Friday.
The Montgomeryshire MP told supporters that more Lib Dems needed to be elected as a "defence of our freedom" in the "battle for civil liberties".
He said the new legislation revealed the UK government had learned nothing from history.
"It has introduced a piece of law which might well turnout to be a recruiting sergeant for terrorism," he told the conference.
"The government says it needs to protect us from those who destroy our way of life.
"I'd say that Wales and Britain needs the Liberal Democrats to protect us from a government destroying our way of life in our name."
On Welsh politics, he argued that the Lib Dems had proved they were "good when we get into government".
The party was in coalition with Labour in the Welsh Assembly Government until the last election in 2003, and Mr Ípik claimed it was the only time it had been stable.
"Without our team of six (assembly members) in power, the assembly government seems unable to lift itself out of the quagmire of process," he said.
He urged party members at the general election to tell voters the difference a Lib Dem government would make.
He said there would be no British troops in Iraq, no detention of people in Britain without trial, and no "plain bloody stupid" council tax.
Party members also urged campaigns to raise awareness among sixth-formers and students of the dangers of drink spiking and "date rape".
The party also called on police to introduced anonymous crime reporting for sex offences and that pub and club door staff should have specific training on how to identify and deal with drink spiking.
Party members were told that 70% of victims of "date rape" had their drinks spiked in a pub, and the same proportion knew their attacker.
The conference agreed that young people in university towns and cities in Wales were at particular risk, because there was a large concentration of pubs and clubs.