ZURICH (Reuters) - Switzerland will implement a new law in July to help seize and repatriate illicit wealth parked in its banks by foreign dictators, the government said on Wednesday.

The move is aimed at helping Switzerland and its wealth management industry shake off their image as a secretive haven for ill-gotten riches.

This issue was in the news again this week when Singapore shut down Swiss private bank BSI's operations in the city-state and Swiss prosecutors began criminal proceedings against BSI in the biggest international crackdown on financial entities dealing with a scandal-hit Malaysian government fund. [nL5N18M01G]

The Swiss cabinet agreed to implement from July 1 a law that lets authorities seize and return funds that foreign leaders looted, even in cases that cannot be resolved through standard international requests for mutual legal assistance.

Three ordinances cover assets previously seized as a precaution from former Presidents Zine El Abidine Ben Ali of Tunisia, Hosni Mubarak of Egypt and Viktor Yanukovych of Ukraine and their inner circles, although all three expire early next year.

"Thanks to these ordinances there is now greater transparency, predictability and legal certainty in efforts to tackle the problem of illicitly acquired assets," it said.

A foreign ministry spokesman said the government had blocked about $650 million in the case of Egypt, 60 million Swiss francs ($61 million) in the case of Tunisia and about $70 million regarding Ukraine.

The Tunisian assets are set to remain frozen until Jan. 18, 2017, and the others until February 2017.

The government will review next year whether to extend the asset freezes. If it does not, the freezes expire and the holders of the money regain control of their assets.

Switzerland has tightened money-laundering laws in recent years and requires financial institutions to enforce "know your customer" rules. These also cover "politically exposed persons" encompassing leaders, ministers and military brass.

Over the past 15 years it has returned nearly 1.8 billion Swiss francs' worth of assets, more than any other financial centre, it says.

($1 = 0.9902 Swiss francs)

(Reporting by Michael Shields; Editing by Hugh Lawson)