Campaigners opposed to the High Speed rail link between London and Birmingham have questioned the consultation process after it emerged that hundreds of responses were omitted from the original analysis.
Former Cabinet Minister and Conservative MP Cheryl Gillan said the project was in "disarray".
Mrs Gillan wants to know if ministers will order a fresh consultation.
The government was accused of being "complacent" and the process called a "shambles" by campaign groups.
Ministers have confirmed that a "very small proportion" of responses were not fully analysed.
The Government is already committed to going ahead with the first phase of High Speed 2 (HS2) is already committed to going ahead with the first phase of High Speed 2 (HS2) which would see ultra-fast trains running from London to Birmingham on a new line which could be completed by 2026.
The total cost for both phases is estimated at £32 billion but campaigners say that it will not provide the economic benefits that have been claimed and it will destroy picturesque landscapes.