Plaid Cymru’s Leanne Wood has urged Wales to “reclaim politics”, claiming racist language is becoming the norm.
She warned of a “dangerous situation” as politicians opened a “can of worms” over immigration.
As her party conference began, Ms Wood claimed the Tories were developing “an ugly, divisive, nationalistic politics” and called for tolerance.
The Welsh Conservatives said she was “hypocritical” to make such comments as the leader of a nationalist party.
Ms Wood claimed there was an increase in hate crime, as well as anti-immigration and anti-refugee sentiment in some UK newspapers, especially since the referendum vote to leave the European Union.
“More and more we hear racist language becoming the norm,” she said.
“I fear we’ve ended up in this situation because of irresponsible politicians trying to use rhetoric against immigration in order to make political points, for example for Brexit.
“But we’ve opened a can of worms now and we are potentially in quite a dangerous situation.”
Ms Wood said people had an “opportunity” to change the tone of the debate, saying: “I want people in Wales to reclaim politics.
“We saw from the Tory party conference, the language, the attempts to try to take UKIP’s base back is developing an ugly, divisive, nationalistic politics.
“We can be much more positive, much more global in our thinking and more tolerant than politics has been in the recent past”.
A spokesman for the Welsh Conservatives rejected the criticism and claimed they were an “inclusive” party.
“Leanne Wood should think twice before bandying around words like ‘divisive’ and ‘nationalistic’ when describing other parties,” he said.
“After all, let’s not forget that she herself presides over a nationalist party whose ultimate aim is to separate Wales from the United Kingdom.”
Ms Wood is due to speak at the Plaid Cymru conference in Llangollen on Saturday.
On Friday, Ynys Mon AM Rhun ap Iorwerth told the conference that “hard Brexiters” mustn’t be allowed to “have the last laugh” on Wales’ future by taking the UK out of the European single market.
“Yes, Wales voted to leave,” he said.
“But I don’t think Wales wants to take leave of its senses when it comes to our economic future.”
Earlier, the conference observed a minute’s silence to commemorate the 50th anniversary of the Aberfan disaster.
Plaid’s Wood in ‘reclaim politics’ call}