THE China Railway First Group will complete the final designs of 14 new bridges by the end of this month.
The designs will then await the approval of Montgomery Watson Hauser Consultatants before construction.
Group project manager Peijun Lei said the existing bridges had been severely damaged from years of use without proper maintenance, and all would be replaced.
"There is a need to build the new bridges as soon as possible in order to ensure the safety of passengers and vehicle operators who use the highway," Mr Lei said.
"The designs of the bridges will be completed by the end of this month and construction will begin once MWH approves the designs.
"However, temporary bridges have been constructed and some of them are currently being used by traffic."
Mr Lei said they were pleading with drivers who used the highway to be mindful of the weight of the trucks and speed while passing through those temporary bridges.
"The temporary bridges can only support a maximum of 40 tonnes and not any more than that.
"Work on the bridge is expected to be completed within two years time."