Te Ururoa Flavell and Tamati Coffey were surprised by the timing of Shane Jones' resignation, saying he will leave a big gap in the Labour Party.
The exiting Labour Party MP said he no longer had the level of commitment or energy his party deserved.
Mr Jones announced his resignation on Tuesday after speaking to Labour leader David Cunliffe and party president Moira Coatsworth.
He has been in talks with Foreign Minister Murray McCully about a possible job in an international fisheries management role.
He said he would leave at the end of next month after reflecting on the decision during the Easter break.
"I no longer have the energy and commitment to bring to the role of being a front bench fighter for the Labour Party, coming into the election and for another three to six years," Mr Jones said.
"The party deserves to be represented by people who have 1000 per cent commitment."
Maori Party's Waiariki MP Mr Flavell said he was not surprised by the decision, but was surprised by its timing.
"He'd signalled something like that to us when we got together as old boys of St Steven's [college] [but] I didn't expect it so soon.
"It will affect the Labour Party as he was a very good performer, very sharp and intelligent.
"I enjoyed our confrontations in Parliament.
"He was an accomplished speaker in Maori and English and he will be missed as he brought a political edge to the party and didn't hold back."
Labour Party candidate for Rotorua Mr Coffey said he saw Mr Jones as "a bit of an elder statesman" in the party and his influence would be missed.
"Ideally you wouldn't have people resigning in an election year, it's the year where the pressure is on everybody," he said.
"But, if his heart was not 100 per cent in it, it's best not to be taking part, so he knew what he needed to do."