A Scottish Government minister has called for the inquiry into the Beauly to Denny power line upgrade to accept new data on potential health risks.
The power line would run from Beauly to Denny
Stirling MSP Bruce Crawford wants a study by leading scientists to be considered despite it being published after a deadline for new submissions.
The study found that current standards for emissions from power lines are inadequate to protect public health.
The 137-mile upgrade would see 600 pylons replacing existing power lines.
Last week deputy Scottish Tory leader Murdo Fraser attacked the inquiry for dismissing evidence as inadmissible on deadline grounds.
Mr Crawford, who is also the parliamentary business minister, said a decision to exclude the report, titled A Rationale for a Biologically-based Public Exposure Standard for Electromagnetic Fields, was "a mistake".
The study looked into the effects of exposure to Electromagnetic Fields (EMF), and expressed concern at current limits which regulate how much EMF is allowable from power lines, mobile phones, and other sources in daily life.
Mr Crawford said: "It is my understanding that the Reporters to the public inquiry are refusing to accept this valuable report because it was published after the deadline for submissions some nine months ago, despite the provision existing to accept it as it was completed and published after the deadline.
"This decision must be mistaken.
"The Reporters have already accepted late submissions from the applicants in this case; however surely the real point is that all relevant evidence available should be accepted and considered.
Mr Crawford called for the new data to be admitted
"It is vital that the most up-to-date studies are taken into account if the correct conclusions are to be reached by the Inquiry."
In response to Mr Crawford's concerns, a spokesman for the Scottish Government said: "The issue of electromagnetic fields was debated at length during the 12-week strategy session of the inquiry in Perth in February 2007.
"The Reporters were not prepared to accept the report's late admittance, some months after the date for lodging documents for the strategy session.
"This decision is consistent with the approach to the admittance of late documents which was outlined by the Reporters at the start of the strategy session."
Scottish and Southern Energy (SSE) want to develop the £320m proposal to transmit electricity from renewable sources via the power line from the north of Scotland to the central belt.
The inquiry is due to continue until the end of the year.