BERLIN (REUTERS) - Senior German lawmakers on Sunday called for tougher rules to make it harder for tax cheats to claim amnesty by turning themselves in, days after soccer manager Uli Hoeness was sentenced for three and a half years in prison for tax evasion.

Recent news that Hoeness and other prominent Germans such as feminist activist Alice Schwarzer hoarded cash in secret bank accounts for years, have prompted calls for Chancellor Angela Merkel's government to clamp down on tax dodging.

"Together with the federal states we want to tighten the conditions for amnesty further," German Finance Minister Wolfgang Schaeuble told Frankfurter Allgemeine Sonntagszeitung.

The finance ministers of Germany's federal states demanded earlier this month that fines for tax evasion be doubled.

Currently, people who avoid paying more than 50,000 euros (S$88,000) in tax face a 5 per cent fine and can apply for an amnesty under certain conditions.

"This fee should be increased," Mr Volker Kauder, parliamentary floor leader of Merkel's Christian Democrats, told Welt am Sonntag newspaper. "That would underline that tax evasion is a serious offence against the general public."

Mr Schaeuble had tried to negotiate a tax deal with Switzerland for years that would have allowed German tax dodgers to come clean anonymously, but the plan stumbled at the last hurdle.

With no new tax deal with Switzerland on the horizon, Mr Schaeuble said he wanted to extend the time period for which tax dodgers must declare earnings or money hidden abroad.

Hoeness said on Friday he would accept his prison term for hiding 27 million euros and resigned from his posts at Bayern Munich, the club he made into one of the world's most successful soccer dynasties.

He had turned himself in but his voluntary disclosure was found to be incomplete and he did not meet the requirements of the current amnesty laws.

Conservative deputy parliamentary floor leader Ralph Brinkhaus said he expected the Hoeness case would be a lesson for tax dodgers.

"I expect that fewer taxpayers will now even get the idea not to pay tax on their income," he said.

But finance expert Lisa Paus from the opposition Greens called for further changes to the current amnesty laws.

"The threshold of 50,000 euros... is way too high and must at least be halved," she told Reuters.

"We must make sure that those who are honest about their taxes are not worse off than those who dodge taxes."