TAOISEACH Micheál Martin has appealed to the contractor and those working on building the National Children's Hospital to get back on the site.
Work has not resumed at the site since the Covid-19 lockdown was eased last month, leading to concerns that the stoppage may already have cost the taxpayer millions of euros.
Building contractor BAM claims delays will continue until a Covid-19 vaccine is widely available.
In a statement, BAM said no more than 1,000 staff can be safely deployed at the site, compared to an estimated 2,000 people needed at peak times.
Speaking in Dublin today, Mr Martin said: "I'm quite annoyed at what has transpired here in the sense of why is it the Children's Hospital site that is one of the only sites that work has not recommenced?
"Work has commenced at construction sites right across the country. It is unacceptable in my view, what has happened here.
"I would say to people, get back out there on-site and start building the children's hospital because the children of this country need it. A lot of investment and effort has already gone into it.
"The only objective has ever been that the children of Ireland would have a world-class health facility that could really genuinely cater for our children.
"I'm angry about this and I think they should get back out on the site. I'm not interested in excuses. I'm not interested in what people are saying and blaming. If they have the interests of the children of Ireland at heart they should get back on site and start building.
"That's my message - I'm sick of claim and counterclaim - get back on site and start working."
Health Minister Stephen Donnelly echoed his comments, saying: "Please get back on site. At pretty much every building site across the country, contractors and builders are back on site.
"There are ongoing issues between boards and developers and there are processes to be resolved. The very clear message is get back on site - the children of Ireland need a new hospital."