The development could draw a line under a three-year row that has pitted Pakistan's top court against the ruling Pakistan People's Party (PPP), cost a prime minister his job and threatened to bring down the government before the end of its term.
At the insistence of the country's Supreme Court, Pakistan wrote to Swiss authorities in October over the multi-million-dollar allegations against Zardari, which date back to the 1990s.
He and his late wife, former premier Benazir Bhutto, were accused of using Swiss banks to launder $12 million in alleged kickbacks.
Yasmin Abbasey, the top official in the law ministry, told AFP on Sunday that the Swiss had said they would not reopen the cases, which were frozen when Zardari became head of state in 2008.
"They have responded to the letter and said the president has immunity," she said.
"This was the main issue and they have confirmed it, that the president enjoys immunity."
Pakistan's top court spent nearly three years demanding that the coalition government led by Zardari's PPP ask the Swiss to reopen the cases, before the politicians finally agreed.
The tussle cost prime minister Yousuf Raza Gilani his job in June last year, when the Supreme Court convicted him of contempt for refusing to obey its orders to write to the Swiss, forcing him out of office.
Critics argued that the court's dogged pursuit of the Swiss cases amounted to a political campaign against the PPP-led coalition government, and said the case had contributed to political instability in the restive, nuclear-armed state.
After Gilani's removal as prime minister there were fears that his successor Raja Pervez Ashraf could suffer the same fate, and that the government could fall before completing its five-year term in March.
As far back as March 2010, Swiss prosecutors pointed out that it was impossible to reopen the cases against Zardari while he was president.
The PPP is facing a tough fight in the general election, which is expected in the coming months.
Should it lose Zardari might lose the presidency and his immunity from prosecution, since the president is elected by parliament.
Political analyst Hasan Askari said the news from Switzerland meant the chapter was closed for now, but warned the opposition would still use the issue to attack the PPP as polls approach.
"It solved their current problem. It has saved the PPP from the propaganda that they did not abide by the supreme court verdict," he told AFP.
"But during the election campaign the opposition will continue to raise the issue of corruption."