Trustees of Whitney Houston's estate have made a legal bid to have payments to her daughter changed.

Members of the trust - including the late singer's mother Cissy - fear 19-year-old Bobbi Kristina Brown is under the ''undue influence'' of unsavoury people and worry the current payment schedule could jeopardise the teenager's long-term financial security.

Court documents filed in Fulton County Superior Court in Atlanta, show Cissy Houston declare Bobbi Kristina ''is a highly visible target for those who would exert undue influence over her inheritance and/or seek to benefit from respondent's resources and celebrity.''

The legal documents go on to explain the trustees are concerned about the ''wasting of trust assets'' if the current payment plan - for which specific details are not given - continues.

The petition adds: ''[The schedule of distribution from Whitney's estate would conflict with her] intent to provide long-term financial security and protection for her child. Compliance with the provisions of the trust would defeat or substantially impair the accomplishment of the purposes of the trust, which were to provide for the proper maintenance and comfort of the respondent, and to prevent the wasting of trust assets, as evidenced by the trust's spend thrift provision.''

Bobbi Kristina - who was involved in a car accident with boyfriend Nick Gordon last week - is the sole beneficiary of Whitney's estate.

The 'I Will Always Love You' hitmaker died in February as a result of accidental drowning.