Investigators also claimed Kundra (36) told them that he lost around Rs one crore in the past three years in betting in IPL matches.
However, police said they have no evidence yet to implicate Kundra in fixing matches.
Shetty, Rajasthan Royals co-owner, denied the allegations on Twitter saying her involvement in betting is "complete nonsense" and that she has "never bet on any cricket match ever".
The tweets were retweeted by Kundra. Kundra, a British national, was questioned for 11 hours yesterday after cricketer Sidharth Trivedi (30) told police that his business partner-friend Umesh Goenka (36) used to ask for information regarding team formation and pitches.
Delhi Police Commissioner Neeraj Kumar said, "He (Kundra) has admitted to betting. He used to bet on his own team. We have also come to know that he has lost a lot of money in betting. He used to bet through Goenka, who is also a bookie."
S N Srivastava, Special Commissioner (Special Cell), said Goenka in his statement before a magistrate informed that he used to place bets for Kundra besides making a reference to Shetty that she also placed bets "once".
"During questioning, Kundra has mentioned that he was placing bets for the last three years and the amount that he lost, all put together, was to be around Rs one crore," he said.
"It is in the statement (of Goenka that Shetty placed bets). We have not gone ahead and verified it as of now. But then we are in the process of verification," he said.
Srivastava said he cannot give a timeline on when Kundra will be called again.
In Kolkata, Jagmohan Dalmiya, chief of the interim BCCI arrangement, said that the Kundra issue will be discussed at the BCCI emergency meeting on June 10 in New Delhi. (MORE)PTI TAQ SJY VMN VMN 06062007 NNNNstrate. This bars him from retracting his statement.
"Raj Kundra issue will be discussed in the Working Committee, which is going to be held on June 10 and after we hear the details, if it demands any strict action, we will look into it," Dalmiya said.
He also said that no BCCI member will be part of the Inquiry Commission comprising High Court judges T Jayaram Chouta and R Balasubramaniam to probe allegations against BCCI chief N Srinivasan's son-in-law Gurunath Meiyappan and CSK.
If Delhi police claims are to be believed, Kundra started betting in IPL matches after getting 11.7 per cent stake in Rajasthan Royals in the third edition of the T20 tournament.
Kundra is the second IPL team owner after Chennai Super Kings' Gurunath Meiyappan who is in the dock for alleged betting.
If the charges against the owners are proved, BCCI can give Rajathan Royals the boot from IPL.
Police have confiscated the passports of Kundra and Goenka to ensure that they do not leave the country during investigations.
Kundra has since flown back to Mumbai and will be quizzed again soon.
According to sources, Kundra became one of the owners of the team in the third season of IPL.
From the next season onwards, Goenka started watching matches along with Kundra, who used give him match passes.
"Kundra used to place bets for the past three years. Kundra used to place bets with Goenka. Goenka was a bookie and forwarded bets to others on behalf of Kundra," a senior police official said.
On the basis of Goenka's statement, he said, they had to call Kundra for questioning.
Reacting to police's claim, Shetty tweeted, "We love cricket, it's the passion for the sport that made us a part of IPL. It's extremely disheartening to keep clarifying that.
"For those who care, my apparent involvement in betting is complete nonsense and I have never bet on any cricket match ever. Truth will prevail. I won't be saying any more as the case is sub-judice," she said.
Police sources said Goenka, who was born in Sikkim, was into share and sponch iron business but he suffered losses.
As he stayed near the residence of Kundra's mother, he became a family friend and later went to London where he met Kundra after his business collapsed.