He said Tory conference announcements on immigration had been "disturbing, sinister and beneath contempt".
Home Secretary Amber Rudd has said new curbs on foreign workers and students may be needed to "change the tide" of public opinion on immigration.
Mr Jones urged Welsh Labour to "fight for the soul of post-Brexit Britain".
In an email to party members, the first minister condemned the Conservatives, saying: "This isn't just dog-whistle politics, it is politics of the gutter."
He said Welsh Labour members should aim to be a "roadblock" to Tory plans to restrict immigration, and show there was "a better way".
"When senior Tories said yesterday that foreign doctors and their families were only welcome here whilst they were needed, I said they are welcome, full stop," he wrote.
"We must reject the Tories' terrible insult to people who work day in, day out to save and improve lives across Wales."
Mr Jones described Brexit as "a seismic and unsettling event in our country's history, and how we react to it will be the measure of this generation of politicians and political parties".
"I have made absolutely clear my belief that Wales must accept the referendum result, we cannot refight that battle, but we can fight for our vision of the future," he said.
"A bright future for our children and grandchildren, based on our values of fairness, internationalism and prosperity for all."
Welsh Conservative leader Andrew RT Davies described Mr Jones's comments as "ludicrous".
"Ultimately, if there is a poisonous atmosphere surrounding the politics of immigration it's because successive Labour governments over 13 years ruthlessly stifled moderate discussion and left millions of people feeling frustrated and ignored," he said.
Meanwhile SNP leader Nicola Sturgeon and Plaid Cymru leader Leanne Wood have joined forces with Green Party leaders across the UK to condemn "the most toxic rhetoric on immigration seen from any government in living memory".
Foreign doctors in Wales will not be told to "go home", Welsh Labour leader Carwyn Jones has said, accusing the Conservatives of "gutter" politics.