Repairs to the Aylesbury Arm of the Grand Union Canal may take longer than first expected.
A lock wall at Buckland, near the Arla dairy in Aston Clinton, collapsed in March, resulting in the route being closed.
It was hoped the canal could be re-opened in time for the August bank holiday, but the Canal and River Trust, which is responsible for the waterway, says that deadline still needs to be reviewed.
Officials are also concerned about the cost of the work, which is expected to be between £400,000 and £500,000.
The cause of the collapse is still unknown.
Canal boats trapped at the Aylesbury basin had to be craned out of the water in April and taken to Milton Keynes so their owners could travel during the summer.