The Scottish Conservatives have warned that needy English pensioners will move to Scotland in search of free personal care, offered by their Scottish Labour and Liberal Democrat opposites.
But the claim, by Conservative Shadow Home Secretary Ann Widdecombe, has been ridiculed by their political rivals.
She warned that poorer pensioners in England would move north to take up free personal care.
Ms Widdecombe's views were later echoed by Scottish Tory Phil Gallie, although the Scottish Tories supported and voted for free care.
First Minister Henry McLeish said Labour remained committed to the delivery of free personal care and he said the Conservatives' input was "nonsense and unhelpful".
Scottish National Party MSP Mike Russell said he felt sorry for pensioners south of the Border who appeared to be getting a rough ride.
The Liberal Democrats claimed that free personal care for the elderly was one of their big successes in the Scottish Parliament.
The row has highlighted the complications that devolution can cause in the campaign for the general election campaign.
Mr Gallie said the delay by the Scottish coalition in implementing the Sutherland Report on care for the elderly had cast doubt over its desire to do so.
He said that if Labour was returned to power and Sutherland was implemented, then an influx of pensioners from south of the Border could place the Scottish economy under severe strain.
'A real threat'
The Scottish Parliament has backed free personal care for the elderly on things such as washing, but counterparts at Westminster have not followed suit.
On Tuesday, Ms Widdecombe said if Sutherland was implemented in Scotland then "you may see people retiring north of the Border. So we'll just have to wait and see what happens to the Scots".
Mr Gallie sided with his southern Conservative colleagues, saying: "It is a real threat, but I repeat again that the Labour Party and the Liberals are not set on introducing Sutherland.
"If they were committed to it then they would have introduced it months ago."
First Minister Henry McLeish said the Tories' comments were not helpful in the slightest.
He said: "I think that kind of comment is both unhelpful and complete nonsense. What I think we are doing in Scotland is looking at the needs and aspirations of the Scottish people.
"Long term care is vitally important."
Mr Russell said the furore highlighted fundamental disagreements within the Conservatives at Westminster and those in Edinburgh.
He said: "Scotland can cope with any number of people that want to come to the country and live here. But the reality is what we are doing in Scotland is trying to provide fairness for our old people.
"If they cannot do that south of the Border then I pity those people south of the Border."
The Lib Dems said the issue illustrated the need for the Westminster government to adopt its policy in the Scottish coalition.
Lib Dem MSP Nicol Stephen said: "We've made a real difference in Scotland and I think they acid test for that is if you ask a teacher, a student or an old person in England, they would want to implement the policies we have here in Scotland."
The Scottish Tories later insisted that Mr Gallie had been expressing a personal opinion on the issue.