MPP Randy Hillier has been accused of working to help unseat fellow Tory Norm Sterling. (Canadian Press)

A bitter fight over the nomination for an Ottawa-area riding is threatening a split in the Ontario Progressive Conservative ranks.

The riding is Carleton-Mississippi Mills, which has been held for the past 33 years by MPP Norm Sterling.

A key player behind the push to remove Sterling is maverick Tory MPP Randy Hillier.

Sterling, a former cabinet minister, has accused Hillier repeatedly of helping his friend Jack MacLaren usurp him in the nomination.

MacLaren is a former president of the Ontario Landowners Association, a property-rights group dominated by rural activists that Hillier helped create.

Ontarians will vote in a provincial election in October.

The rift widened when Hillier's friend, federal Tory MP Scott Reid, wrote a letter to a Toronto newspaper in December accusing Sterling of neglecting his constituents.

The growing feud means PC Leader Tim Hudak is facing tough questions about whether or not he can control Hillier.

Hudak deflects the questions by saying what his party is really interested in is defeating Dalton McGuinty in the October election — and looking after their ridings.

“Our members will continue to do what they've been sent [to Queen’s Park] to do, which is focus on representing their constituents,” said Hudak.

Now Hillier's activities are also the subject of a complaint to Ontario's integrity commissioner.

Although Premier Dalton McGuinty vowed to stay away from pre-election mudslinging in the legislature, the Liberals filed the complaint alleging Hillier is abusing tax dollars for partisan political activity.

Their complaint says Hillier is using his taxpayer-funded MPP website to help an email fundraising campaign by Sterling's rival.

The nomination will be decided in late March.

With files from The Canadian Press