Law, who was arrested and given just two hours to leave the country, expressed outrage on ABC radio.
"I'd get better treatment in the Congo, you know, because I was seriously jostled and pushed by the arresting officer," he said. "It was quite unpleasant."
Chief Justice Geoffrey Eames condemned his treatment, saying: "The magistrate here was dealt with like a criminal. You'd think he was Tony Mokbel [a convicted drug trafficker who disguised himself to avoid arrest] in a wig."
Eames, who issued an injunction aimed at preventing Law's deportation, was denied a visa to travel to Nauru and deal with the matter.
He said the Government's actions were "politically motivated, designed to have the decisions [about the businessmen] overturned by a new magistrate".
According to Fairfax Media, Eames had expressed serious misgivings to the Nauru Government about the conditions in which asylum-seekers are held on the island.
He also opposed attempts to have the cases involving the riot - which caused A$6 million ($6.4 million) of damage - held at the detention centre and to exclude the media.
Earlier this month, Nauru increased the cost of a journalist's visa from A$200 to A$8000, which was condemned by the Australian Greens as an attempt by Tony Abbott's Government to "shut down public information about how Australian taxpayer money is being spent on the cruel and harsh detention camps on Nauru".
Law's sacking was ordered by the Nauruan President, Baron Waqa, whose Government was elected in June last year.
Rod Henshaw, one of the two businessmen decreed "prohibited immigrants" by the Justice Minister, David Adeang, was close to the previous government, acting as its media adviser.
Lately Henshaw, a former ABC broadcaster, had been running a bar at the government-owned Menen Hotel.