THE Fiji Roads Authority has identified possible shoddy workmanship and use of substandard material as reasons behind last week's Kings Rd slip.
The Babavoce section of the Kings Rd cracked and slipped more than a metre after continuous rainfall pelted the Central and Eastern divisions.
The cracks forced the FRA to work overtime to clear a single lane for cars with new works diverting traffic over a hill behind the road.
"We believe the slip has occurred as a result of several factors," FRA maintenance works manager Dale Nicholls said.
"Not controlling the water adequately coming off the hill behind the slip, poor construction during the initial build and potentially using substandard materials."
Mr Nicholls explained the Babavoce section of the Kings Rd was built in 1989 and had not been rehabilitated since.
He added it was supposed to be resealed this year but the slip had put a halt to these plans.
"The fill at this site has failed at least twice previously with the most recent failure in 2010.
"The 2010 slip failure was not as severe as this current one and the road was able to be closed to one lane without needing to reopen the old Kings Rd."
Mr Nicholls said weaknesses in the road infrastructure would be revealed in extreme weather events like TD15 and there was no guarantee that road slips would not occur again.
Meanwhile, pending the authority's final damage assessment, it says it estimates road damage to be more than $10m.
He said works at damaged roads were in progress but no timeframe could be given on when all remedial work will be completed.