St Kilda and Essendon are demanding answers from the AFL after the roof at Marvel Stadium was left open as rain swept through the Docklands on Friday afternoon.

Both clubs arrived at the venue ahead of Friday night’s clash and were left surprised by parts of the turf being wet under foot.

Rain was predicted throughout the afternoon, but the roof remained open until they made the call to shut it just after 2pm. The process takes 20 minutes to fully shut, which allowed plenty of water to come in.

Know the news with the 7NEWS app: Download today

The ground remains slippery ahead of the opening bounce at 7.20pm.

7NEWS reporter Xander McGuire revealed the matter has immediately been raised with new AFL footy boss Greg Swann.

“Frustration at Marvel Stadium - where the roof was left open for a period of time as rain swept through Docklands with the ground still slightly wet,” he said.

“The matter has been referred to Greg Swann and the AFL.

“Both teams filthy - particularly the Saints.”

“The feeling is that you come to an indoor stadium, you expect the conditions to be perfect,” he added on 7NEWS Melbourne.

St Kilda coach Ross Lyon fired up his rarely used X account to post about the issue.

It was just his seventh tweet in 12 years.

“Oh no might be hard Marvel Stadium did not manage to close the roof before the rain came,” he said with two laughing emojis.

Lyon was watching the pre-match legends game organised by Essendon.

He later told Channel 7 that the turf can be like a “car park” when it gets wet.

“Apparently there had been eight minutes of rain, which is OK if it’s at the MCG, but here it’s like a car park, rock hard, very difficult,” he said.

Marvel Stadium says they closed the roof in the afternoon when light rain began to fall and remain confident the turf will be fine throughout the match.

“It won’t be the last we hear of it,” former Collingwood coach Nathan Buckley said on Fox Footy.

“Whatever the spectacle of this game is, if the skills aren’t great or there are players falling over, it’ll be a point of conversation.

“It’s something you just shouldn’t get wrong.”