Magistrates are reportedly ignoring police recommendations and not imposing travel bans on football hooligans.
Police do not want a repeat of Euro 2000 violence
Laws brought in last month make banning orders easier to use but a source told BBC News a quarter of convicted troublemakers still escaped them.
But the Home Office played down the concerns, raised ahead of England's friendly against Portugal on Wednesday.
Minister Hazel Blears told the BBC: "We have 2000 banning orders now, when we only had 100 a couple of years ago.
Speaking on Radio 4's Today, she added: "I think that is a pretty good sign magistrates are keying into this.
"They know it's much better to prevent the trouble happening in the first place than to try and clear up the mess."
About 2,500 tickets have been made available to English fans for the "high-risk" fixture in Faro.
The authorities in England and Portugal are treating it as a dress rehearsal for England's opening matches of the Euro 2004 championship in Coimbra and Lisbon in June.
About 50,000 England supporters are expected to travel to Portugal for the tournament - more than for any other nation.
Police are keen to avoid a repeat of Euro 2000, which saw hundreds of England fans rioting in Belgium.
Violence also marred the European finals in Italy in 1980, in Germany in 1988 and in Sweden four years later.
Police say they want another 600 banning orders in place before Euro 2004 kicks off.
Since August, 67 operations in 28 police forces have led to 134 banning orders being issued.
And the Home Office has given forces across the country £5m to finance specialist operations aimed at securing banning orders for as many suspected hooligans as possible.
Ms Blears is visiting the Portuguese university
town of Coimbra, the setting for England's second Euro
2004 match, on Tuesday.
She will meet the town mayor, Carlos Encarnaca, and tour the stadium, 100 miles north of Lisbon, where England play Switzerland on 17 June.
On Wednesday, Ms Blears will watch the match in Faro, on the Algarve coast.
"This will be a test match for how things might turn out at the tournament," she said.
"We will test out some of our ways of working."
On Monday, Ms Blears signed a memorandum of understanding with her Portuguese counterpart, Nuno Magalhaes, to confirm the UK Government's commitment to stop about 2,500 English hooligans travelling to Portugal through the use of banning orders.
Afterwards, Ms Blears said: "We will do everything we can to
ensure those with banning orders do not travel and that the banning orders
But the statement also said English police would monitor all England supporters travelling to Portugal.
And any individual not banned but against whom there was evidence they posed a risk to public order in Portugal would be intercepted, prevented from travelling and face banning order court proceedings.
"We are absolutely determined in England to do
everything we can to make sure that people in Portugal enjoy the football," Ms Blears added.