Just days after Western Australian Greens and co-deputy leader Senator Scott Ludlam resigned immediately when it was revealed he had not renounced his New Zealand citizenship, Senator Waters, the other deputy leader, realised she was a dual Canadian citizen.
Senator Waters last month made history by becoming the first woman to breastfeed her child while passing a motion before the Senate.
Laws, that changed a week after Waters was born, mean the senator was Canadian from birth and must have actively renounced her Canadian citizenship. "As people would know after the recent departure of my dear friend and former colleague Scott Ludlam, section 44 of the Australian constitution means I can not hold office in the federal Parliament", Waters said in a statement.
In a statement, Ms Waters said she had not visited Canada since leaving as a baby and believed she had naturalised to Australia.
Ms Waters was born in Canada to Australian parents and came to Australia as a baby.
In an emotional press conference she held in Brisbane on Tuesday, Waters said if she had been born a week later, she would not be in this position.
"I've never been back". In Waters' case, this would be Andrew Bartlett, a former senator with the Australian Democrats who left the Senate in 2008.
England's Tammy Beaumont chasing place in sell-out Lord's final
In the first of the two semi-finals, at Bristol, the England eves will square-off against their South African counterparts. Saikat (fourth umpire ), Steve Bernard ( match referee ).
"The challenges we face as a nation are still so great, and I will not be stepping away from them", she said.
The resignations mean the Greens have lost two of their strongest performers in Australian Parliament in less than a week.
Ms Waters was seen by some in the party, including former leader Bob Brown, as a future leader of the party. Larissa acted quickly as soon as he knew about it and she has paid a high price for this.
"It has been an honour to work with my Greens colleagues in the parliament and in the Queensland party", she said.
"I have spent my working life protecting the environment and helping the community have better say in decision making, and that will not cease".
Waters said while it was "my job to check", the Greens would review their selection processes.