The frame is made in Taiwan by Giant or Nishiki they mass produced bikes for many low end brands such as Repco in Australia from the late 80's to mid 90's after local production became to expensive to be profitable.
If it has a serial number starting with a G it would be made Giant if not its a Nishiki.
Here's a 1988 Repco Superlight as an example I bought for $2 people still do them up down here into good looking bikes.
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