Singapore-based Tiger Airways says its Australian domestic services are likely to remain grounded until at least August 5.

The budget carrier said Australian aviation authorities have issued it with a set of formal conditions that the airline must comply with before domestic flights can be resumed.

Tiger said it will refund all passengers booked to fly between 1 August and 4 August.

Tiger said a further announcement on the resumption of service from August 5 would be made at the appropriate time.

Australia's Civil Aviation Safety Authority grounded Tiger's fleet in June on safety concerns after two planes flew below the safe-altitude limit within one month.