I don’t really know where to start with this, you say that this is a new development (I think). Has the scheme had its first meeting and elected a Committee? Has a budget and levies been set?
Dingo is right, if there is a gas leak then it has to be fixed, and quickly. The issue is, again as both you and Dingo have noted – is the gas leak a matter that is something that is the responsibility of the developer under the warranty? In that respect I am not sure why you would say the builder would not vote for repairs – he/she may well do that if it gets them out of being responsible for the leak.
So call the strata manager and ask them:
– was the gas leak something that should have been repaired under warranty
– if so, why wasn’t a claim made?
Re the notice of meeting, also ask the manager why you didn’t receive it.
If the scheme doesn’t have enough money to fix a gas leak, you should start looking at your budget and how much you should be paying in levies.