State Sen. Sonia Chang-Diaz is defending the ethics bill that her colleagues unanimously signed off on last week. The Senate version of the bill is getting a “bum rap,” said Chang-Diaz, who bested former Sen. Dianne Wilkerson in a Democratic primary last year, before federal corruption allegations arose against the longtime incumbent and forced her to resign.

The bill imposes stiffer penalties for ethics violations and bans campaign contributions from lobbyists. The penalty for bribery would be increased to 10 years in prison and a $100,000 fine. But the bill drew criticism from government watchdog groups and Gov. Deval Patrick, who has threatened to veto the bill if it transfers some powers away from the State Ethics Commission.

The Senate also adopted measures in the House version of the bill, which provides subpoena powers to the secretary of state and allows the state attorney general to call a statewide grand jury. The bill, which does not touch the matter of the Ethics Commission letting Wilkerson collect thousands in cash as gifts, now goes to a joint Senate-House committee to hash out any differences before heading to the governor’s desk.

Chang-Diaz, who delivered her first speech in the Senate last week on the bill, said the proposed changes to campaign finance law were more important than the changes to ethics, since ethics rules already have penalties in place.

Corruption allegations occurred not because of holes in ethics laws, she said. “It’s because people chose to break the rules that do exist,” she told the Reporter.

Wilkerson, who is awaiting trial, has pleaded not guilty to the charges.