The void was discovered by Amber Geyelin, a negotiator at Robert Luff, while she was at work last Saturday.
Amber was ‘going about her business’ when she heard the road crumble.
She said: “I heard a loud bang and a bus pulled up outside. I looked out and you could see a dark hole. I was alarmed when I spotted it.
“People were crossing the road, looking in and taking pictures.”
Amber alerted the police and the county council, who arrived to make the area safe. However the hole remains as it was, surrounded by barriers, more than a week later.
Amber added: “I thought they might have chucked something down there to make it less dangerous.”
Kerry Laker-Body, 32, of Hatfield Walk, Worthing, first saw the hole last Monday.
She said: “As the days have progressed it’s got bigger. I was quite concerned driving around it. It’s quite scary that nothing’s been done about it. It looks really deep.
“They do seem to be appearing here there and everywhere, and with the horror stories of people’s cars going down the holes you would hope they dealt with it fairly quickly.”
A spokesman for West Sussex County Council said: “The site has been made safe while we investigate the circumstances surrounding the appearance of this void.
“We are liaising with various utility companies to establish the cause.”