Nationals candidate Shane Sali said he and his team were thinking of Dr Haines, her family, friends and team.
One Nation candidate Phil Bryant commented on Facebook that it was “terrible news”.
“Thoughts and prayers go out to Helen and her family,” Mr Bryant said.
The attack occurred on the afternoon of Monday, October 19 outside Dr Haines’ office in Wangaratta.
The Federal Member for Indi remained in a critical condition on the afternoon of Tuesday, October 20 and doctors were reportedly working to save her second leg.
A vigil was held for Dr Haines at Wangaratta’s Holy Trinity Anglican Cathedral on Tuesday afternoon.
Mr Sali said that political discussion should not attack individuals and encouraged more policy-focused rhetoric.
“When it gets personal, it’s not an environment we want in and around our communities,” he said.
“We need to focus on the ball, don’t play the player.
“We want to be kind and caring of all people in the political environment.”
Mr Sali praised Dr Haines for her commitment to regional Victoria and said she was a lovely person.
“I pray and hope she can get through this,” he said.
Independent candidate Lou Costa said she was lost for words and that her campaign manager was a friend of Dr Haines.
“We’re thinking about her today,” Ms Costa said.
“We shouldn’t be made afraid.”
Labor candidate Cayla Fin said she was devastated by the news and her thoughts were with Dr Haines, her family, team and community.
“Violence has no place in our homes, our streets, our hospitals or our democracy,” Ms Fin said.
“Take care, be kind.”