The Tesco Extra petrol station, at the Holmbush Centre, in Upper Shoreham Road, closed on Sunday, August 14, so the petrol pumps could be replaced.
It was due to re-open tomorrow (Saturday, August 20).
When engineers began to dig up the forecourt, however, they discovered unexpected problems with the pipes, causing a three day delay.
The petrol station will now re-open at 8am on Tuesday.
Store manager Graham Murray said: “Unfortunately the petrol station renovations are going to take longer than expected.
“I would like to apologise for any inconvenience this has caused our customers, however, their safety is of the utmost importance.
“I can confirm that as of 8am next Tuesday, our petrol station will be open, safe and the pumps will be much quicker to use.
“I’d like to take this opportunity to thank our customers for their patience.”