"Justice Shetty has been operated upon for his stab wounds and is recovering. He is likely to be kept in the hospital for another week," chief cardiac surgeon at Mallya Hospital Divakar Bhat told news agency IANS.
Mr Shetty, 73, was stabbed by a 33-year-old complainant, Tejraj Sharma, on Wednesday afternoon and was rushed to Mallya Hospital in the city centre. The attacker was immediately arrested by the police.
The incident has raised questions over security at the office of the Lokayukta.
After the attack, a non-functioning metal detector at the Lokayukta's office has now been replaced with one that works.
"A police team led by Joint Commissioner of Police (Crime) N. Satheesh Kumar is probing the incident of attack on Justice Shetty. I am expecting the report soon," Home Minister Ramalinga Reddy tweeted on Friday.
"There is complete lawlessness. It has come to such a state that a Lokayukta is also attacked. Now people are asking, if Lokayukta is not safe, who is safe in this state," Union Minister Prakash Javdekar said. Mr Javadekar also visited Mr Shetty along with BJP leaders Piyush Goyal and leader of the opposition in the state, Jagdish Shettar at the hospital.
"We were extremely shocked to see the news. Our prime minister, party president, Amit Shah were extremely disturbed. The leaders from Karnataka met the prime minister and expressed deep concern about the deteriorating law and order situation in Karnataka. The honourable prime minister was extremely disturbed," Mr Goyal said. He said the Lokayukta was recovering well and that his life was not in danger.
The incident has spurred strong political reactions with the state preparing for elections later this year.
The BJP had already been attacking the Congress government on law and order issues - with Prime Minister Narendra Modi and party president, Amit Shah raising the issues in political rallies in the state.