"We will be calling bids again as some arithmetical inaccuracies and errors were found in the documents tendered by the lowest bidders", official sources said on Wednesday.

The sum total of the figures in each page of the documents submitted by the lowest bidders did not tally with the final figures, the sources said.

The 15-stretches, together accounting for 202 kms, were estimated to cost over Rs 600 crore. All the stretches were to be completed through budgetary support.

A total of Rs 2,500 crore is to be raised by the government this year for developing national highways through the cess on diesel and petrol.

Already, the government has awarded contracts for five stretches totalling 63 kms (Rs 200 crore). Prime Minister Atal Behari Vajpayee had launched theambitious 7000-km long road project in Bangalore on January 3.

NHAI had targeted awarding contracts for all the 20 sections of the corridors by March 1999.

But the fresh process for the 15 locations was likely to delay the process by another two months, sources said.

After calling for fresh bids, NHAI would open the tenders in front of the parties concerned and evaluate them on the spot this time as a measure of `abundant caution'.

The Prime Minister's Office was monitoring the progress of the project and they wanted to avoid any controversy over awarding the contracts, sources said.

The 15 sections for which the NHAI was likely to call for fresh bids are Delhi-Samalkha at Haryana, Delhi to Haryana stretch of NH-1, parts of Agra-Gwalior stretch of NH-3, Agra-Dholpur section of NH-3, Chambal-Morina (NH-3), Nagpur-hyderabad (NH-7), Salem bypass (NH-7), Palanpur stretch of NH-14, Lucknow-Kanpur (NH-25) and NH-25 stretch inside Kanpur city.

The other sections are two stretches of Purnia-Ghayakota onNH-31, Dhalka-Islampore (NH-31) and Guwahati bypass (NH-37).