Prime Minister Giuseppe Conte "will attend on Sunday", Salvini said, despite casting doubting over Italy's presence at the summit the day before.
"Either there is a useful proposal on the defence of borders, security and on the rights of true refugees or we dare to say no," he said on Thursday.
Salvini's earlier threats came after extracts from a draft of the concluding statement from the mini-summit circulated in the media. He said he would "save the money" for the trip if Italy would have to sign an agreement "already written by the French and the Germans".
According to the Italian press, Rome feels that the leaked extracts do not sufficiently address the protection of European borders and focus excessively on the redistribution of migrants once they are already in Europe.
- What will Italy's new government mean for migrants?
- Rejected migrant ship is 'symbol of EU's failure'
- Italy calls for tougher reforms of EU's asylum rules
European Commission chief Jean-Claude Juncker called for the crisis talks on migration between the leaders of ten EU countries as the issue causes fresh divisions in Europe.
But Conte on Thursday said he had received a call from German Chancellor Angela Merkel who was "worried" that Italy may not attend.
"I confirmed to her that it would be unacceptable for me to attend this summit with a pre-written text," he wrote on Facebook. "The chancellor has made it clear that there has been a misunderstanding: the draft text circulated yesterday will be shelved," he concluded.
On Wednesday Conte held a meeting with EU President Donald Tusk in Rome. After the talks he tweeted that Italy did not want to discuss "secondary movements" – referring to dealing with migrants already in Europe – without having addressed the "emergency" issue of the arrival of migrants on EU soil "that Italy finds itself facing alone".
The country's new populist government accuses fellow EU members of abandoning Italy as it struggles to cope with migrants making the perilous journey from Africa across the Mediterranean. Italy has seen more than 700,000 migrants arrive on its shores since 2013.
Earlier this month Salvini thrust the issue of immigration to the forefront of the EU agenda when he refused to let an NGO ship carrying over 600 migrants dock in Italy. The ship was later welcomed by Spain.