Mr Amiri was given asylum in New Zealand after the Australian Government denied him refugee status.
He was one of 433 Afghanis rescued in the Indian Ocean by the Norwegian container ship Tampa in 2001.
He believed New Zealand was not considered a destination by people-smugglers, and that a campaign for tougher laws on asylum seekers would alert smugglers to New Zealand instead of putting them off.
"I didn't have a clue about New Zealand when I travelled to Australia. Creating detention centres ... is just telling people-smugglers that we exist."
Five oral submissions heard yesterday were mostly critical of the bill, and either wanted it dropped or amendments made.
The New Zealand Law Society submitted that the present processing system was robust enough to cope with mass arrivals.
Spokesman Rodney Harrison challenged the assertion that the tougher rules would deter asylum seekers.
He added that to do so would breach New Zealand's human rights obligations.
Committee chairman David Bennett cited a submission which said New Zealand and Australia's humanitarian policy made the countries a target for boat people.
Dr Harrison responded: "The argument then seems to be that because we've been chosen by reason of our humanitarian treatment of refugees that we should react by treating them inhumanely."
The new law defined more than 10 refugees as a "mass arrival" and allowed a group of this size to be incarcerated for up to six months.
Dr Harrison: "Under this regime, if you have 11 who arrive, they are all treated as just members of a single category and none of them individually has the right to challenge that mass detention."
Refugees who arrived in groups of up to 10 would be individually assessed for security risk and had the right to appeal if they were detained.
JustSpeak spokesman David Smith argued the amendments encouraged a culture of incarceration. He accepted the need for an initial processing period, but said groups of people fleeing persecution should not be treated more harshly than some criminals, who had the right to bail or curfew.
THE CHANGES
Immigration Amendment Bill:
* Defines more than 10 asylum seekers as a "mass arrival".
* Allows mandatory detention for mass arrivals for up to six months.
* Gives greater powers to suspend processing of refugees.
* Makes it more difficult for refugees to have their asylum claims reviewed.