Formula One's governing body would need to carry out a full safety assessment before agreeing to any night-time race, FIA president Max Mosley said on Monday.
"We wouldn't sanction night racing for Formula One without a very careful investigation," the International Automobile Federation (FIA) head said.
Formula One supremo Bernie Ecclestone and Singaporean property billionaire Ong Beng Seng have been discussing the possibility of holding a race under floodlights in the south east Asian city state.
Ecclestone is keen on the idea, which would boost European television audiences due to the time difference but some drivers and team bosses have expressed concern about safety issues.
Double world champion Fernando Alonso said this month that he considers the idea to be impossible.
"There are all sorts of factors there, some of which have been highlighted and some of which haven't yet, and we want to look at that very carefully before we sanction it," said Mosley, attending the launch in London of a UN global road safety week with former world champion Michael Schumacher.
Mosley does not rule out, however, the possibility of a Singaporean night race appearing on the calendar as early as next year.
"So far there hasn't been an application but if there is a serious attempt to run a night race then we will have a very careful look at it," he said.
"We have a safety commission which looks specifically at these problems and they will probably come up with a number of recommendations and research to undertake before saying okay, because it would be a big step and we wouldn't want to make a mistake.
"One must not underestimate the logistics, the degree of lighting that will be necessary for really good television coverage, the cost, the complications and all the things that go with it," continued Mosley.
"But that's not really our problem, all we would be concerned about would be the safety aspect."
GREAT START
Mosley expressed satisfaction with how the first three races of the Formula One season, the first since the retirement of Ferarri's seven-times champion Schumacher, have gone with three separate winners and three joint championship leaders after Bahrain.
McLaren rookie Lewis Hamilton, the first driver to finish his first three races on the podium, had also made a big impression.
"The impressive thing about Lewis Hamilton is that he hasn't put a foot wrong, and that's what's so unusual with a beginner...that's really impressive," he said.
"We've been fortunate. But we mustn't put too much on Lewis Hamilton. If things don't go so well for him for a few races, it doesn't mean anything. He's obviously got a huge future in front of him."
Mosley said rule changes since the end of last season, with engine development frozen and the departure of Michelin leaving Bridgestone as sole tyre supplier, has shown no adverse effect.
"What's interesting is that the hugely controversial engine freeze, nobody seems to notice. It's made no difference. The only difference is that it's saving the big manufacturers probably about a billion euros a year.
"What I now hope is that the cars stay evenly balanced, and that nobody pulls out a huge lead," added the Briton.
Mosley said the glamour sport still needs to make overtaking easier and to encourage wheel-to-wheel racing:
"That's going to take time, but we are working on it," he said.
