It follows UKIP leader Nigel Farage's comments on migrants using the NHS for HIV treatment costing Â£25,000 per year.
On the Daily Politics Wales Election Debate on Thursday, Lib Dem Jane Dodds said UKIP lacked "care and compassion" on such healthcare issues.
UKIP's Caroline Jones said Ms Dodds was "taking things to extremes" but claimed people were "fed up to the back teeth".
Ms Jones told the programme that she understood Mr Farage's comments that the NHS was treating too many people from abroad with HIV.
She said: "Is it fair when you've got a small pot of money to allow someone to come in who has never contributed to that pot, and have someone from your family or your constituency to be denied medication and treatment?
"That is constantly happening."
But Ms Dodds said everybody should have fair treatment, asking "Do you want border security guards on hospitals?
"Do you want GPs' surgeries to have lines that say 'do not cross here unless you've paid into the system for five years'?
"Where is the care and compassion here?"
Plaid Cymru's Carrie Harper said debate about immigration should not be taboo as it was an issue that voters wanted to discuss.
"But this type of scaremongering and the blaming immigrants for everything rhetoric is very unhelpful to the debate," she added.
"The economic problems facing people in our communities have been caused by the reckless behaviour of bankers in the City, and they've been caused by the austerity agenda of the London parties."
For Labour, Nick Thomas-Symonds said the NHS would not be able to function without migrant workers.
"The National Health Service is the greatest achievement of any post-War government," he said.
"There is no doubt at all factually that without migrant workers working in it, you wouldn't have an NHS in 2015."
For the Conservatives, Emma Lane said immigration had been beneficial to the UK.
"Immigration can and has benefited our country but it must be managed," she said.
"We need to control immigration so the pressure doesn't continue on public services".

The Marine Accident Investigation Branch (MAIB) said it was difficult to keep the vessel Millennium Time on a steady heading before it struck a tug on the River Thames in July 2014.
The report also said the man at the helm at the time of the crash did not hold a boatmaster's licence.
City Cruises apologised and said passenger safety was "paramount".
The nine injured passengers suffered cuts and bruises when the boat struck motor tug Redoubt, which was towing three barges between Blackfriars and Waterloo bridges on the Thames on 17 July 2014.
The 69-year-old mate's employment as a helmsman was contrary to the instructions of the Millennium Time's operators, City Cruises, the report said.
And the 58-year-old master of vessel was providing a sightseeing commentary, meaning he did not supervise the mate at the helm, the report concluded.
The MAIB said the mate did not take immediate action to avoid the vessel's collision with Redoubt because he thought the motor tug was turning towards Millennium Time, but Millennium Time had unexpectedly steered towards the motor tug.
The report said: "The turn was not deliberately initiated by the movement of the helm and most likely resulted from the unintended application of port rudder, and/or the influence of the effects of (an aquatic phenomenon known as) hydrodynamic interaction."
By the time the helmsman noticed the vessel was turning the collision could not be prevented, the MAIB said.
The report added the crew were also unaware of the number of passengers onboard - they thought they were carrying 426 people but the police counted 362.
Both vessels were damaged and it took 32 days to repair Millennium Time's damage, which included broken windows.
The MAIB, which made a number of safety recommendations, said City Cruises had replaced the steering systems on Millennium Time and its sister vessels.
In a statement, City Cruises said its vessels undergo rigorous testing and the helmsman was in the process of completing his boatmaster's licence.
Spokesman Kyle Haughton said: "The safety of our passengers and crew is paramount to us.
"The report does not highlight one significant reason for the accident and refers to a number of contributing factors."
A Welsh Liberal Democrat election candidate has accused UKIP of wanting "border security guards" at hospitals.
[NEXT_CONCEPT]
A pleasure boat involved in a crash that injured nine tourists had steering problems, a report has said.