Sinn Fein president Mary Lou McDonald has described the current coronavirus crisis as a greater "accelerant" to a united Ireland than Brexit and has called for an all-island approach to health.
Describing the lack of a single health policy between Northern Ireland and the Republic as "astonishing", Ms McDonald told the Sunday Times newspaper that in her view the current situation "dwarfs Brexit in terms of reflecting the danger of partition".
"When Brexit happened, people said this is an accelerant in terms of the unity debate, because it was so obvious with the danger to the border," she said.
"We have an all-Ireland single policy for animal health but not for public health.
"Everything we do to keep people safe has to be on the understanding we are a single population on a small island and have to look after each other."
Ms McDonald has only recently returned to work after having been diagnosed with Covid-19.
She is likely to become the leader of the opposition in the Dail if Fianna Fail and Fine Gael can successfully form a coalition along with the Green Party.
In her remarks on Sunday the Sinn Fein leader was also critical of Prime Minister Boris Johnson's initial "herd immunity" approach.
Reflecting the well publicised disagreements in the Stormont Executive around the pace and direction of particular Covid-19 restrictions, she said there had been robust conversation and debate between the parties here around which policies and approach to follow.
"I think the fact that Boris Johnson and the British Government opted early on for the herd immunity approach meant that Michelle O'Neill had to have some pretty tough conversations to get the northern system in tandem with what was happening in the South," she added.
"Yet again we see how vulnerable we are when we have two jurisdictions, two systems, on the island."