Mr Tuck said de Malmanche, in custody in Bali's Kerobokan prison, knew the executions were inevitable, but the aftermath was still devastating.
"He knew both Andrew and Mayu quite well. And they had supported him."
Mr Tuck spoke to de Malmanche this afternoon.
"We always knew it's a dangerous situation and this just backs up that the Indonesians have the political will to carry out the death penalty."
This morning's firing squad executions, in which six other convicts were executed alongside the Bali Nine ringleaders, went ahead despite substantial international condemnation, especially from Australia.
Mr Tuck said diplomatic or political attempts to strongarm Indonesian authorities over the Bali Nine were obviously ineffective, even counter-productive.
He said the Indonesian response to such pressure must be understood through a historical and political context -- specifically, any situation where Indonesian authorities felt they were being "stood over" by a neo-colonialist power would backfire on Western countries.
"Australians have found out how dangerous it is to engage in a political discourse where a specific meaning is taken from the other side."
Yet Mr Tuck said Indonesia's perceptions of Australia were very different from its view of New Zealand.
New Zealander Owen Pomana visited Indonesia this week to support the two condemned Australians and their loved ones.
On Facebook, the former criminal turned Christian evangelist promised to sound a shophar (traditional musical horn) and perform a haka "so my brothers shall know we love them".
Mr Pomana earlier told the Herald on Sunday he gave Chan his All Blacks jersey and the pair performed an impromptu haka at the end of a Christmas Eve service on a previous visit.
"There is hope for prisoners and we can be transformed," Mr Pomana wrote online.
This evening he said on Facebook he planned on flying to Sydney for the funerals.
Australian Foreign Minister Julie Bishop said Chan and Sukumaran's bodies would be transported back to Australia by Friday.
Meanwhile, Mr Tuck said his client's health was deteriorating, as de Malmanche faced the prospect of several more weeks of prosecution evidence at the trial.
"Tony had another angina attack about three days ago so he may or may not be at court tomorrow," Mr Tuck said. "They have taken him to the hospital two or three times. They've done tests."
Mr Tuck earlier said de Malmanche had a head injury which made him slow to process information.
The lawyer said his client's son Andre died a decade ago, aged just 7, and Mr de Malmanche was on medication for ongoing back and neck pain and suffered long-term depression.
"He's a typical Kiwi guy that's in a situation where he needs a lot of help and support," Mr Tuck said today.
"He just wants to be back in New Zealand and get back to Wanganui and just get on with his life. This is all overwhelming for him. He's under tremendous stress."
Mr Tuck said probably another $50,000 was needed to adequately defend de Malmanche.
"We're still considerably short of [funding] to pay for the lawyers and all the proper research and preparation for his trail. So anybody that assists there, we're humbled by it and incredibly grateful," he said.
Supporters have established the Antony de Malmanche Legal Fund on the Givealittle website.
"Just operating on a shoestring all the time is hard yakka especially [with] the translation bills and all sorts of things. It's just never-ending," Mr Tuck said.
