Germany will veto Romania and Bulgaria joining the Schengen passport-free zone if the two countries push their membership at an EU meeting this week, Friedrich warned on Sunday.
"The expansion of the Schengen zone is only accepted by our citizens if the basic requirements are ensured. That is currently not the case," he said, matter-of-factly.
But some may have heard faint echoes of 1960s British racist Enoch Powell when Friedrich last week said, "We are the country which has until now been able to keep far-right parties out of the national parliament. But that will only remain the case if we continue to take the worries of the people seriously, and the problems are solved."
Talking to the Rheinische Post regional paper, he added, "If people in Germany have the feeling that their solidarity and their openness are being abused, and our social security system is being plundered, there will be justified anger."
"The current figures are troubling but can be dealt with," he went on. "But this can take on a new dimension from 2014. When people tell each other what is possible in Germany with social welfare, we should brace ourselves. Organisations that specialise in illegally opening the way to social welfare in Germany for citizens from poorer countries will spring up like mushrooms."
He was referring to changes due to come into force in 2014 that will allow people from Romania and Bulgaria to work in Germany without restriction - just as Poles, Greeks and other people from within the EU are able to.
Confusion over entitlements
Conflicting information about how much social support they may be entitled to in Germany adds to a confusing debate that is often fuelled as much by fear, xenophobia and prejudice as anything else.
Although German authorities say new immigrants are not entitled to social support for at least their first three months in the country, those who sue for it generally win, lawyer Aiko Peterson told last Friday's Süddeutsche Zeitung.
There is also a perceived problem of people from Bulgaria and Romania falsely registering as self-employed and then picking up work on building sites. The change of rules in 2014 will undoubtedly lead to an increase in immigration, said Gunilla Fincke, manager of the Expert Commission on Integration and Migration.
But she told the Süddeutsche Zeitung "in reality most of the migrants are already here. They will just be able to legalize their work situation."
Pressure on German services
Any increase in those so poor they cannot provide for themselves or their children will put more pressure on German social services - and regional governments are already complaining that they are having trouble coping.
A recent report from German Association of Cities said they were hard-pressed by increased costs in housing, schools and other social support due to poverty stricken migrants.
Professor Joachim Trebbe, media analyst at Berlin's Free University, told The Local the continuation of the euro crisis and the inability of struggling countries to get unemployment under control would mean that increasing numbers of people would flock to Germany for work.
But he also noted that not only was Friedrich gearing up for the September 22 general election, as a Christian Social Union politician he is involved in the Bavarian state election scheduled for a week earlier.
'Good immigrants' are invisible
"Migration will be an issue - people will continue to come to Germany from Spain for example, where unemployment is at 26 percent. Migration will increase, and even though the negative consequences are proportionally small, they will also increase. We have the highest level of migration to Germany of a decade, and that will become a theme.
"The IT worker from Spain will come, and will learn German and will not be visible as they go to work. But along with them will come a share of immigrants who are less successful, and they will be visible as they will not be in work."
He said those people who come to Germany and end up homeless were highly visible to voters. The kind of measures promised by politicians such as tougher safeguards to prevent social security fraud and extraditing those who do, would do little to solve the underlying problems, he said.
The fact that living in Germany from begging or eking out child benefit payments is considered a viable option for some among the poorest people in Romania or Bulgaria has less to do with Germany than the terrible conditions they face at home.
Trebbe said efforts were being made using money and political pressure within the EU to improve their lives at home, but that this was a slow process often not helped by corruption in the target countries.
"And it is not so visible to voters. Helping to improve conditions in Romania does not win elections. Clearing a park of the people sleeping in it does," he said.