BUDAPEST (Reuters) - Hungary's government will submit a tougher version of its "Stop Soros" bill to parliament next week, adding criminal penalties for groups accused of financing illegal immigration, Prime Minister Viktor Orban's chief of staff said on Thursday.

The legislation, which would empower the interior minister to ban non-government organisations that support migration and are seen as a national security risk, is part of the nationalist right-wing government's campaign against Soros, a Hungarian-born U.S. financier known for funding liberal causes.