"If an official apology doesn't arrive, prime minister Conte would be right not to go to France", Salvini told reporters after demanding that France take in more migrants.
Salvini called on France to apologise and said he was not prepared to take criticism from a country that regularly stopped migrants on their shared border.
But after Italy and Malta refused entry to the ship, two Italian boats escorted the migrants to Spain - co-operated by SOS Mediterranee and Medecins sans Frontieres (MSF), who offered them "safe harbour".
Euronews correspondent Anelise Borges is on board the vessel, which is expected to arrive in Valencia in four days.
The M5S-League government says that current European Union rules, which require migrants to seek asylum wherever in Europe they first arrive, leave Italy and its southern neighbours bearing the brunt of mass migration across the Mediterranean. Salvini's League scored its best election result in March elections after pledging to deport an additional estimated 500,000 unregistered migrants.
The office of Finance Minister Giovanni Tria confirmed Wednesday's meeting with Bruno Le Maire had been scrapped.
The move comes hours after Italy summoned the French ambassador to the foreign ministry in Rome.
France sought to take a more conciliatory tone on Wednesday.
But Italy's foreign minister, Enzo Moavero, kept up the barrage by telling a French envoy that Macron's comments were "unjustifiable" and had compromised bilateral relations.
"Spain wants to report us, France says I'm "nauseating".
Salvini insisted Tuesday that the country's ports would no longer be open to foreign boats carrying migrants.
Amid mounting cross-party concern that German asylum policy is in disarray, Seehofer, of the Bavarian conservative CSU party, met Austria's chancellor, Sebastian Kurz. "We assure the Italian government of our complete support", he said, adding that he hoped Italy's stance "can bring a change to Europe's migration policy".
"I speak in the name of a government but I also have the ambition of speaking for a people who have nothing to learn from anyone about generosity, volunteerism, welcome and solidarity", he said.
On Wednesday morning, an Italian coast guard vessel with 937 migrants and two bodies aboard docked in Catania, Sicily, while the Aquarius headed into increasingly rough seas on its way to Valencia, where it is due to arrive on Saturday.
However, the Sea Watch is still waiting to pick them up after asking for a written guarantee that it will be allowed to dock in an Italian port.