Engineers responsible for a major project at Marlow’s river lock say they are confident the job will be done before the boating season starts despite the half million pound job suffering setbacks.

The £480,000 Environment Agency (EA) scheme will see the defective timber lock gates dating back to the 1970s replaced with new steel doors with an 80-year lifespan.

Workers have been forced to extend the closure at the Thames lock for ten days because of leakage problems, meaning the waterway will not reopen until at least March 2.

But the EA insists the work is necessary to ensure smooth operation when the season gets back into full swing.

EA spokesman Freya Dean said: The Environment Agency are under a duty to manage their works safely for all concerned, as well as to secure best quality and contract value.

"However, the programmes can be at risk of delays and further lock closure extensions. These decisions are not taken lightly and only as a last resort after considering all other reasonable and safe options, and methods of working.

"Due to minor leakage on the head gates, the Environment Agency have decided to extend the closure until Monday 2 March 2015.

"Engineers have made this decision to ensure we do not have to further inconvenience our customers within the new boating season."

Navigation through Marlow Lock is impossible whilst the work is taking place, so a temporary lock closure has been put in place.

However, high water levels and currents this winter have led to warnings for boats to avoid the area, hampering the efforts of work crews.

During the closure, the EA says it will also widen walkways to minimise the risk of falls on the lock side.

Marlow Lock is in near constant use during the summer boating season, with 16,313 powered and non-powered boats passing through the gates last year.

The work is part of the EA’s winter programme, with six out of ten projects complete and the remainder due to be completed to allow for full length river navigation before Easter.