A Leeds road that has been closed all day is set to remain shut through the night.
The A64 is closed due to the leak, which began on Tuesday (August 28), with engineers on site attempting to fix the problem on the westbound carriageway.
And now, Highways England are advising motorists that the busy road in and out of Leeds isn't set to re-open until Thursday morning at the earliest.
Northern Gas said in a statement: "Northern Gas Networks engineers will work throughout the day today (Wednesday 29th August) to repair a leak on a medium pressure gas pipe on the A64 in Leeds.
Motorists on the A1(M) trying to get to Leeds are advised to use the following diversions:
Travelling northbound on the A1(M):
Continue north to Junction 45 and leave on the A58, join the A6120 and then on to the A64.
Travelling southbound on the A1(M):
Continue to Junction 46 at Colton and then use the A6120 and then rejoin the A64.
If anyone smells gas or suspects carbon monoxide please call the National Gas Emergency Service on 0800 111 999.