BERLIN, Aug 21 (Reuters) - Germany's main opposition party, which has threatened to bloc a tax deal with Switzerland arguing it is too lenient on tax evaders, wants to renegotiate the deal, one of the Social Democrats' leaders told Reuters on Tuesday.
Switzerland and Germany struck a deal in April to levy taxes on German assets in Swiss accounts but Germany's Social Democrats have said they will block it in the Upper House, Bundesrat, saying it is too lax. Its opposition to the deal has strained relations between the two countries.
"We are generally not at all against a tax agreement with Switzerland," Nahles told Reuters. "If Switzerland is ready to negotiate on a new basis, then we will not be the ones preventing a new agreement. But that would really have to be fair. What's on the table now is not fair."
She said a new deal should be along the lines of an agreement between the United States and Switzerland, in which American authorities have pressured banks in Switzerland to divulge the names of account holders and financial details. That deal still needs to be ratified by the United States.
North Rhine-Westphalia, which is governed by the Social Democrats, has bought leaked Swiss bank data on CDs - trying to catch out tax evaders who attempt to move their money before the deal comes into effect, planned for early next year - and Nahles said they would continue to do so.
"I don't see that the SPD will give its approval in the Bundesrat on the basis of the current agreement. On the contrary, we will continue to buy tax CDs to prevent that money being sneaked past the tax man," Nahles said.
Switzerland has said the deal to tackle German tax dodgers hiding money in secret Swiss accounts cannot be renegotiated but Nahles reiterated the SPD would not pass the deal in the Bundesrat.
"What we have now looks like a Swiss cheese with lots of holes, where money is sneaking away and the banks are even giving helpful tips," Nahles said.
The deal has already been renegotiated once, setting higher tax rates in a bid to please the SPD.
Under the pact, German account holders would remain anonymous but Switzerland would impose a retroactive withholding tax on capital in offshore bank accounts and would tax future interest income from these accounts.
German Chancellor Angela Merkel's government, which does not have a majority in the Upper House, has said a tax deal could net Berlin huge sums if and when it takes effect. Germans hold an estimate 150 billion euros in Swiss accounts.
Nahles reiterated the claim that Swiss banks were supporting tax evasion.
"Now that it is clear that the Swiss banks actually support tax evasion, we have to speak out on that clearly," she said.
SPD leader Sigmar Gabriel said earlier this month there had been "organised crime in Swiss banks" helping Germans avoid tax evasion but Swiss bankers and politicians have denied the allegation.
Banking secrecy is key to Switzerland's $2 trillion offshore wealth management industry. The Swiss government has refused an automatic exchange of information on account holders and is pursuing instead the strategy of a withholding tax to preserve secrecy. (Reporting by Annika Breidthardt; Editing by Susan Fenton)