Under the new legislation, which came into effect at midnight (2200 GMT yesterday), police arrested 60 people for "cutting or damaging" a razorwire barrier along the Serbian border.
Another 114 people were arrested throughout the day, and officials immediately began criminal proceedings.
"Police have launched criminal procedures against them," Gyorgy Bakondi, chief adviser to Prime Minister Viktor Orban, told a news conference.
The new laws are part of Orban's strategy to stem the flow of migrants -- more than 200,000 so far this year -- who cross Greece then the western Balkans before reaching Hungary on their way to western Europe.
The changes mean that crossing the border illegally can result in a prison term of up to three years, rising to five years if people damage the razorwire or a more substantial four-metre-high barrier which is still under construction.
Budapest today effectively sealed off its southern border with Serbia, blocking a gap in a razorwire barrier where many of the migrants passed through, as well as closing two official crossing points.
"The number of illegal border-crossers has already reduced significantly," government spokesman Zoltan Kovacs told reporters at the same news conference.
Hungary is also planning another anti-migrant fence along along part of its border with Romania, a minister said today.
Hungary, a member of the European Union and the passport-free Schengen zone, has been sharply criticised over the fence it is building along the Serbian frontier, and today, Romania denounced the new construction plans as "out of step with the spirit of Europe."
Romania is in the EU but not in Schengen, while Serbia is in neither.
"We don't want to turn the country into a fortress but we want to protect our borders," Kovacs said.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
)