The Hungarian government unveiled a tougher version of its package of planned laws targeting NGOs funded by the American billionaire George Soros on Tuesday.
Prime Minister Viktor Orban's government accuses Soros of encouraging illegal immigration into Europe.
As in the original version of the law drafted last month, a tax of 25 percent would be levied on foreign funding given to organisations considered to be "supporting" illegal immigration.
The new draft also retains provisions banning entry to Hungary for foreigners suspected of supporting the entry of asylum seekers, and for preventing Hungarian citizens from approaching the country's border regions if they are similarly suspected.
In addition, the latest version would see NGOs having to undergo a "check" by the security services before being authorised to operate.
"If NGOs refuse to apply for this permission, or if it's refused, a fine will be levied, and if the violation continues, they could be banned from operating," government spokesman Bence Tuzson told reporters on Tuesday.
He acknowledged that this particular measure would need a two-thirds majority in parliament. Analysts say this makes it unlikely the proposals will progress any further before parliamentary elections on 8 April, where Orban is expected to win a third term in office.
Twenty-four Hungarian NGOs condemned the original proposals in January as "dishonest" and said the real target was not Soros but domestic criticism of the government.
Soros has donated to several NGOs in Hungary supporting civil society. He rejects the accusations levelled at him by the government, calling them "distortions and outright lies" and based in part on anti-Semitic tropes.
Last year the EU took Hungary to court over legislation targeting the Soros-funded Central University in Budapest.
The EU action also relates to measures adopted in June which mean that groups receiving more than 24,000 euros ($26,000) annually in overseas funding must register as a "foreign-supported organisation", or face closure.