The United States said it was "deeply saddened" by the shooting, adding: "We condemn this senseless act of violence and join Tanzanians in expressing our honest hopes for his full and speedy recovery".
He serves as chief whip for the parliamentary opposition and is president of Tanzania's bar association, the Tanganyika Law Society, as well as being CHADEMA's attorney general.
"I've been saddened by the gun attack on Tundu Lissu, I'm praying to Almighty God that he may recover soon", a translation of the first of two tweets issued in Swahili read.
"State organs should hunt down the criminals involved in the terrible act and face the full force of the law", the president added.
Regional Police Commander Gilles Muroto said they have launched investigations into the shooting but preliminary reports show that people who attacked Mr. Lissu were in a white Nissan vehicle.
"We are appealing for calmness as the MP was receiving treatment", he told a joint news conference.
According to Tumaini Makene, spokesman for the main Opposition Chadema party, Mr Lissu had multiple wounds after the shooting and was treated in a public hospital in the capital.
"I cannot say at the moment how many bullets lodged in his body but he was shot in the stomach and legs".
James Kiologwe, a doctor at Dodoma regional hospital, said Lissu was in stable condition.
He was arrested in July for calling the president a dictator, and again in August for saying the Canadian Government had detained a jet bought by the Tanzanian Government over an unpaid $38m debt to a Canadian company.
However, a number of lawyers defied the call and attended court proceedings as in any other days, saying the TLS had no mandate to order them to boycott court proceedings.