The investigation into cash-for-honours allegations is damaging politics, senior Labour figures have admitted.
Ms Blears believes the inquiry is having a "corrosive effect"
Party chairman Hazel Blears said it was causing a "corrosive cynicism" and constitutional affairs minister Harriet Harman said it was "eroding trust".
Their comments came as Downing Street revealed that police had twice quizzed Tony Blair as a witness in the affair.
Parties have been accused of rewarding donations with honours. All those questioned have denied any wrongdoing.
Ms Blears told BBC News she feared the police inquiry was overshadowing the government's domestic agenda.
"I want the investigation to be brought to a conclusion as quickly as possible," she said.
"Inevitably when you have this kind of thing going on for months and months it does have a corrosive effect."
Mr Blair's second interview with detectives took place last Friday in Downing Street, but was kept secret by the prime minister until Thursday at the police's request.
He was previously questioned in December. Both interviews were not conducted under caution, which means he is being treated as a witness rather than a suspect.
Labour's chief fundraiser, Lord Levy, and Downing Street aide Ruth Turner have both been arrested on suspicion of perverting the course of justice. Both were released on police bail, without charge.
It is understood Lord Levy was asked about meetings with senior staff at Downing Street at which he is believed to have discussed honours.
The inquiry was sparked after it emerged Labour had received secret loans before the 2005 general election from people who were subsequently nominated for peerages.
As well as Labour figures being quizzed, police also interviewed ex-Conservative leader Michael Howard.
About 90 people have been interviewed during the inquiry so far.
Ms Harman said an elected House of Lords would help end controversies like the cash-for-honours inquiry.
She told BBC Question Time: "I don't think we should be having patronage through the honours system - with or without the money.
"I think it should be elected."