The expected result is the distribution of the burden of resettling refugees more effectively and evenly among member states.
The deal follows weeks of diplomatic wrangling over migrant rescue ships, and which country should take them in.
Later on Friday the Libyan coastguard said around 100 people were thought to have drowned off Libya's western coast.
Where would the centres be built?
Conte also openly denied what French President Emmanuel Macron had said earlier about new asylum processing centres, namely that they can be set up only in "frontline" states, which include Italy but not France.
A consensus needs to be found on the Dublin Regulation to reform it based on a balance of responsibility and solidarity, taking into account the persons disembarked following Search And Rescue operations.
Numbers illegally entering the EU have dropped 96% since their 2015 peak, the European Council says.
"An ever greater number of countries is becoming convinced that the best solution is not to forcibly relocate refugees [within the EU] nor to impose fines on countries that refuse to accept them, but to expand our collaboration to help those countries which are the source of the refugee flows to Europe, as well as to harden the external borders of the European Union", said Prime Minister Mateusz Morawiecki. "It was a long negotiation but from today Italy is no longer alone".More news: Anthony Kennedy's Retirement Is A Bad Sign For Fixing Gerrymandering
Theresa May has been told by Europe's leaders it is the "last call" for her to set out her Brexit plans if she hopes to achieve a deal with the European Union on the UK's future relationship in October.
At the crux of Merkel's problems at home is the issue of migrants coming to Germany after already registering in other European countries in what's known as "secondary" migration. "They weaken us on the European and global stage - and in an economically challenging situation". "But this is in fact the easiest part of the task, compared to what awaits us on the ground, when we start implementing it". If we want to reach a deal in October, we need quick progress.
However several Central European states have so far rejected an EU scheme to relocate 160,000 refugees from overcrowded camps in Greece and Italy.
While Macron takes pride in finding a European solution for migration crisis, the language of the deal suggests that EU's dealing with migration will be as cruel and inhumane as that of the United States that has attracted global condemnation for its latest assault on "illegal migrants" tearing families apart.
Merkel said she would inform her coalition partners, including her hardline Bavarian allies, about the details of the deal on Friday evening.
Merkel and Seehofer, who heads the CSU, have been at odds over his proposal to turn some migrants away at Germany's borders and his threat to push through that plan unilaterally.
This would cost Merkel her parliamentary majority.
The prime minister's focus on the security partnership came against a backdrop of European Union frustration about the lack of progress in the divorce talks and her own failure to give details of the future trading relationship she wants with the bloc.
According to IOM data, 52,240 migrants or refugees arrived in Europe as of June 20 this year, compared with 186,768 in 2017 and 390,432 in 2016.