The president of the rightwing Swiss People's Party, Ueli Maurer, has called for the government to replace Micheline Calmy-Rey as foreign minister.
But the sole candidate to take over as president of the centre-right Christian Democratic Party, Christophe Darbellay, has defended Calmy Rey's stance in the Lebanon crisis.
Calmy-Rey, a member of the centre-left Social Democratic Party, has been increasingly under fire for her comments on Lebanon, particularly after a speech she gave last Monday at the annual conference of Swiss diplomats in Bern.
"The foreign ministry needs a different leadership. There should be a change of ministry at the latest in 2007," Maurer said in an interview with the SonntagsZeitung.
At the diplomats' conference Calmy-Rey had attacked both the United States and the European Union for their policies in the Middle East and defended her view of "active" neutrality, which included Swiss criticism of human rights violations.
She also supported the idea of a Swiss seat in the United Nations Security Council.
Earlier, Calmy-Rey had described the Israeli intervention in Lebanon as "disproportionate".
Maurer said that Calmy-Rey should no longer represent Swiss interests outside the country "with her one-sided comments". She should only remain responsible for development aid, he added.
He also said that the issue had become a matter of principle. When a government minister continually expressed a different view from that of the government, that person should be relieved of his or her portfolio.
Maurer put forward the name of defence minister and party colleague Samuel Schmid as replacement for Calmy-Rey, saying that Schmid was born for the job, being both reserved and prudent.
The SonntagsZeitung interpreted his demands as possible election strategy that could polarise opinions.
In defence of Calmy-Rey, Darbellay said she deserved more praise than criticism for her position.
Darbellay, who is a member of the House of Representatives from canton Valais, told the Südostschweiz am Sonntag newspaper that Calmy-Rey's criticism of the Israeli intervention in Lebanon was not a problem.
He distanced himself from the more conservative members of the People's Party, saying their idea of neutrality with eyes closed and lips sealed was not his style.
On the contrary, neutrality had to be alive and active, which was what Calmy Rey was encouraging.
However, Darbellay said he was not in favour of a Swiss seat in the UN Security Council, arguing that Calmy-Rey's remarks on the issue had been a "super present" to those who put neutrality on a pedestal.
swissinfo with agencies
Micheline Calmy-Rey has earned both praise and criticism for her recent comments on Swiss foreign policy.
At last Monday's conference of Swiss diplomats, she called for a stronger international political role for Switzerland, arguing that a seat in the UN Security Council would be a "productive" step forward.
She said Switzerland did not have the critical mass to resolve crises on its own.
She argued that Swiss foreign policy lacked visibility and was limited in its scope.
Switzerland, she added, was increasingly dependent on what happened abroad.
Her remarks have sparked a renewed discussion about Swiss neutrality.