Unite Union leader Mike Treen is back in New Zealand with "a few stories to tell".
Earlier this week Mr Treen was detained after taking part in an attempt to break the Israeli blockade of Gaza, which has been in place since 2007.
His flight touched down at Auckland Airport shortly after midday.
Mr Treen says he, and fellow flotilla members, were Tasered and had their belongings confiscated. While in Hong Kong, on his way back to New Zealand, Mr Treen said everything he had was "stolen" in Israel, including most of his money.
"Now have no phone, computer etc," he wrote on Facebook. "I am using another deportee's laptop. He was a journalist and treated a bit better."
In addition to the Tasering, Mr Treen says he had his foot "stomped on, but we gave them a bit of a message as well".
Green MP Marama Davidson offered him words of support on Wednesday night. She took part in a flotilla to Gaza in 2016, and was also detained.
"I remember that return trip well - arriving home to my family was such a relief. I remember feeling that with everything I had experienced after being taken hostage by the Israeli navy, spending time in Israel jail and then being deported all the while having had no communications with anyone - I felt super homesick.
"But nothing I had experienced came close to what the Palestinian families and children must bear every day in a humanitarian crisis that restricts their access to water, power, medical supplies, basic economic development and most importantly - their dignity.
"So thank you Mike for this important solidarity work."
Then-Prime Minister John Key said Ms Davidson's participation in the flotilla was a "less-than-perfect look" for New Zealand.
"Probably to be frank, it would be better if they didn't."
The Embassy of Israel in New Zealand said in a statement on Tuesday that the flotilla was a violation of international law and "a cynical publicity stunt designed to divert the attention from the fact that Hamas, with its brutal ruling of Gaza since 2007, invested in terror instead of the welfare of its people."
The legality of Israel's blockade of Gaza is disputed. While the United Nations has regularly called on Israel to end the blockade, its own investigations have reached mixed conclusions as to whether it's legal or not.
International rights groups, such as Amnesty International and Human Rights Watch, largely view it as illegal.