The Conservative Party chairman will face an investigation into her use of MPs' expenses to pay a nanny... at her own request.
The Parliamentary Standards Commissioner John Lyon said the "exceptional" circumstances meant a full inquiry should take place into Caroline Spelman's case.
A statement from his office said: "Having carefully considered the matter, the Commissioner has recommended to the (Standards and Privileges) Committee that exceptionally he should conduct an inquiry. The Committee has accepted that recommendation."
It emerged earlier this month that the Meriden MP paid Tina Haynes to look after her children and do secretarial work for a "short-term period" after her election to Parliament, between 1997 and 1998.
However, it emerged last weekend that Ms Haynes in fact remained on the public payroll for almost two years, from April 1997 to March 1999.
The nanny is also thought to have lived at Ms Spelman's family home in Kent for some of the time - more than 140 miles from her West Midlands constituency.
Ms Spelman insists she did nothing wrong in employing Ms Haynes. She says the nanny was doing administrative work at her home - which she was using as her constituency office - as well as providing childcare services outside school hours.
The arrangement was ended after she consulted the then Tory Chief Whip James Arbuthnot - although the party has insisted both sides were convinced she had not broken any rules.
After the story broke, Ms Spelman held a meeting with Mr Lyon on 9 June and asked him to investigate in an attempt to clear her name.
The Commissioner's statement said that after "careful" consideration he had agreed to Ms Spelman's request, "despite having received no formal complaint about her conduct and that the events complained of were more than seven years ago".
It went on: "The Commissioner is therefore initiating an inquiry into whether the circumstances of Mrs Spelman's employment of her secretarial assistant from 1997 breached the rules of the House in force at the time."
The news comes amid a slew of sleaze allegations against Conservative politicians.
The Tory leader in the European Parliament, Giles Chichester, resigned when it emerged he transferred more than £400,000 of staff expenses into a private family company.
And the party's chief whip in Strasbourg, Den Dover, was replaced after insisting there was nothing amiss in paying his wife and daughter a reported £758,000 over nine years through a company for secretarial and support services.Reuse content