I don't know about Ireland but that's definitely not true for Germany. While the amount usually talked about in negotiations is pre-tax (since people have differing tax rates due to children, marriage, etc.), there's a significant difference from there to the actual cost to the company.

In my company we pay about 25% on top for social security, worker's benefits, health insurance, etc. This is without any company-provided benefits such as trainings, conference allowances, holidays, etc.