When illegal migrants enter a country they have one of two paths to support themselves financially, they take low paid un-taxed jobs or they claim benefits from the country if there are any. This results not only in competition for legal citizens in the country but also causes a loss of tax revenue, that hurts government spending, a study conducted by the Federation for American Immigration Reform found that the total annual cost to the US from illegal immigration is $113 billion. Theses costs can mount up as many illegal migrants will be using a country’s education system, causing costs to rise as they do not contribute to the national schooling system, and the same applies to hospitals if the country provides healthcare. Legal migration is a costly endeavour, the easier illegal immigration becomes the more migrants will feel inclined to migrate illegally, illegal migration therefore has a lot of hidden costs to a society's economy.
This argument is misplaced, in reality illegal migrants (sometimes with language difficulties) could not take jobs or claim benefits without a social security or national insurance number, so they are instead exposed and limited to exploitative casual low-pay (and often illegal) employment. These are jobs that natives of the country won’t often take anyway, and the same could be said for welfare and social benefits, as countries have to keep records on who is taking what as the government inevitably has to pay these costs. It is a myth that illegal immigrants pose a strain on social welfare, and it is a myth they are taking jobs away, more likely they are keeping the economy afloat by carrying out menial jobs that natives citizens often will refuse for the low wages, hard work or long hours. Many countries have a labour shortage internationally and those countries should be protecting and using illegal migrants as the asset they are. Furthermore a lot of illegal immigration and a labour shortage is a sign of the need to change migration policy, and states should think of immigration in general as a sort of tax investment, the state could achieve higher tax revenue if they made it easier for illegal migrants compared the expense of enforcing strict anti-immigration laws. This would in fact have a double tax boosting effect, as due to circumstances illegal migrants facilitate tax dodging labour industries, if illegal migrants were treated more fairly governments could seek tax from all migrants and employers.