"It is temporary problem which only affects certain banks and only for cash withdrawals," a SBA spokeswoman told AFP.
She explained that some banks were reticent to allow cash withdrawals from their German customers, to ensure the tax deal agreed to in August between both countries but as yet unsigned is implemented correctly, and not emptied of its content through withdrawals or the closure of accounts.
However, the concerned banks would still make electronic transfers, even to accounts in Germany, she said.
The tax deal, expected to be signed in the German capital on Wednesday, ends a long-standing dispute between the two countries.
Under the accord, Swiss banks agreed to pay 2 billion francs ($2.26 billion) to German tax authorities.
The deal could snare up to just short of 1,000 tax cheats over two years.
German taxpayers would be given a one-off chance to make an anonymous lump sum tax payment, with the tax rate to vary between 19 and 34 percent of the assets.
Any taxes collected from these voluntary disclosures would be offset against the two billion franc advance payment and refunded to the Swiss banks.
In the future, all investment income and capital gains arising from assets held by German taxpayers would also be covered by a withholding tax of 26.375 percent.
The agreement would have to be approved by both countries' parliaments before entering into force in early 2013.
However, some German parliamentarians have already signaled their opposition.
The finance minister of North Rhine-Westphalia, Norbert Walter-Borjans, on September 12th threatened to block the deal.
"I will do everything to prevent the indulgence given to tax frauders," said the social-democrat minister in an interview with German magazine Spiegel.
According to German media, between €130 billion and €180 billion are hidden in Switzerland, which could therefore raise up to 54 billion in taxes for Berlin.