A company owned by Liberal Party identity Matt Daniel lobbied Canada Bay council for an extension to a proposed rezoning that would have benefited Liberal MP John Sidoti as joint owner of a commercial property.

On Tuesday it was revealed that Mr Sidoti failed to include in his latest declaration to Parliament his part ownership of the property at 120 Great North Road, Five Dock, which will potentially benefit from a rezoning decision supported by Liberal councillors.

Mr Sidoti's septuagenarian parents, Catherine and Richard Sidoti, are joint owners of the property. The rezoning proposal, which has been sent to the planning department, includes a new lane behind the property that would give it valuable rear access for the first time.

Following the revelation Mr Sidoti, who is the MP for Drummoyne and parliamentary secretary to Premier Gladys Berejiklian, updated his register of interests and apologised for the "oversight".