Geneva/Berlin - Switzerland and Germany are friendly neighbours and big commercial partners, but a war of words over banking secrecy is shaking the relationship, and few punches are being pulled.

Fights between friends and family can be nastier than enemies.

The row started a week ago, when Peer Steinbrueck, Germany's finance minister, said in an off-the-cuff remark that so-called tax havens were running scared, like Native Americans fleeing mounted troops.

"The cavalry in Fort Yuma doesn't always need to ride out, sometimes it's enough for the Indians to know it's there," Steinbrueck said.

German officials have insisted the comment was not directed at Switzerland, whose German speakers - the largest of four language groups - have a tendency to feel like the youngest child in the Teuton family, at times bullied by its elder.

"We are aware that even simple images can be perceived very sensitively by you. There may be several explanations for that," German Finance Ministry spokesman Torsten Albig told a Swiss journalist.

From the other end, a Native American group also weighed in, telling a Swiss newspaper it found the German official's remark insulting.

Helvetic Foreign Minister Micheline Calmy-Rey described Steinbrueck's comments as "contemptuous and aggressive," and Berlin's ambassador to Bern was duly summoned by the Swiss government.

The remarks were made after countries with banking secrecy laws, including Switzerland, Liechtenstein, Austria and Luxembourg, agreed to make changes, open up files and fight tax evasion.

Germany, along with France, had been spearheading the campaign against the secrecy laws ahead of the upcoming Group of 20 (G20) meeting of leading economies in London, saying the existence of tax havens encouraged their citizens to avoid paying into national coffers.

For many Swiss, whose national pride had been repeatedly dented by the attacks on their banking laws and an ongoing US tax fraud lawsuit aimed at the nation's flagship UBS bank, Steinbrueck's statement was like salt on open wounds.

And so, the Swiss struck back, pulling out a sensitive analogy reserved for special family feuds.

Steinbrueck, said conservative Swiss politician Thomas Mueller, bore similarities to Nazi-era Gestapo police agents.

"He reminds me of the old generation of Germans who, 60 years ago, went through the streets with leather coats, boots and armbands," said the member of parliament last week.

The German minister then said he was receiving hate-mail and being called a Nazi.

On Monday, Switzerland's Defence Minister Ueli Maurer, a conservative, traded in his government issued German-made Mercedes S-Class for a Renault, in protest over the remarks which Steinbrueck has not taken back.

Steinbrueck and Swiss Finance Minister Hans-Rudolph Merz who holds the country's rotating presidency, have said they would meet, though no date has been set.

Luxembourg also weighed in with its opinion, as its Finance Minister Luc Frieden said the tone should not be "dictated by a country's size."

Germany should not "pretend" that it forced the changes to the banking laws, the Grand Duchy's Prime Minister Jean-Claude Juncker also said in Brussels last week.

The current spat is not without precedent.

Back in October 2008, Steinbrueck had upset Switzerland during an international conference on tax evasion in Paris, where he said of the attempt to crack down on banking secrecy laws, "We mustn't just use the carrot, but also the stick."

Germany is Switzerland's largest trading partner, and around 250,000 German nationals live and work in the smaller neighbouring state.

The 7.5 million Swiss, who speak French, Italian and a derivation of Latin called Romansh, alongside the lilting Swiss German dialect spoken by the majority, are fiercely proud of their independence.

Germans, on the other hand, can at times be lured into thinking of their alpine neighbour as an extension of their own language domain, eliciting from the Swiss a mix of indignation and wariness of their looming neighbour. (dpa)