By Steve Scherer

ROME (Reuters) - Italy will boost deportations of migrants who do not have a right to stay in the country and open new detention centres for those being sent home, Interior Minister Marco Minniti said on Wednesday.

The Interior Ministry said in December it would take a tougher stance on migrants this year, without giving details. In testimony to parliament, Minniti described his plan publicly for the first time.

Italy took in a record 181,000 boat migrants last year, and more than 9,000 have arrived already in 2017, a sign people smugglers in Libya continue to operate with impunity.

"We have to deport those who do not qualify for protection and are in violation of the law," Minniti told lawmakers in the lower house. Fewer than 4,000 migrants were deported in 2015. No official numbers have been published for 2016.

To increase deportations, Italy plans to open some 16 new detention centres to hold migrants before they are sent home, Minniti said. Only four pre-deportation detention centres are now functioning. All 20 will have about 1,600 beds, he said.

That would still accommodate only a fraction of migrants without permits of stay estimated to be living in Italy. The country rejected more than 60 percent of the almost 124,000 first-instance asylum requests last year, data show.

Minniti first announced his intention to increase deportations less than a month after the Berlin truck attack by Tunisian Anis Amri that killed 12, including an Italian woman.

The Tunisian came to Italy by boat in 2011. Italy later tried without success to deport him back to Tunisia. He was then released from a detention centre and ordered to leave the country in 2015.

Minniti said Amri had been released because it had not received a timely response from Tunisia recognising him as one of their citizens.

"I'm trying to activate the re-entry agreements we've made over the years. I went to Tunisia to ask them to speed things up. If the response time had been only a month, Amri would have been deported," Minniti said.

Amri was shot dead in Italy by police days after the attack in Berlin.

After a half million migrants arrived in Italy over the past three years, some 175,000 asylum seekers are living in Italian shelters. Minniti said there must be new legislation to try to shorten the asylum process.

Migrants who are rejected asylum can appeal to the court system, extending the average time for a definitive response to an asylum request to two years, Minniti said.

"It takes too long for asylum seekers, and it takes too long for the communities that host them," Minniti said.

(Reporting by Steve Scherer; Editing by Alison Williams)