It is extremely unlikely that an Australian decimal coin with minting errors survived the inspection process and went into general circulation. The closest acknowledgement of an error on an Australian 2 cent coin is that in 1967, 1968 and 1981, the designers initials were left off the reverse of the coin. If it turns out that you do have an Australian coin with a genuine minting error, take it to a reputable coin dealer for a valuation.
Such a coin does not exist. The first Australian 10 cent coin was issued in 1966.
Such a coin does not exist. The Australian 2 cent coin was first issued in February 1966.
Such a coin does not exist. The first and only round Australian 50 cent coin issued for circulation was issued in 1966. There was a round commemorative Proof coin issued in 2006, but not for circulation.
There is no Australian 1954 20 cent coin. Decimal currency was introduced in 1966.
There is no Australian 1950 20 cent coin. Decimal currency was introduced in 1966.
Such a coin does not exist. The first Australian 20 cent coins were issued in 1966.
Such a coin does not exist. The first Australian 20 cent coins were issued in 1966.
Such a coin does not exist. There were no Australian 1967 50 cent coins minted.
Such a coin does not exist. The Australian 2 cent coin was first issued in 1966 on the introduction of decimal currency.
Such a coin does not exist. The Australian "cent" coins were first introduced in 1966.
Such a coin does not exist. The Australian 1 cent coin was first issued in 1966. The Australian One Penny coin was issued from 1911 to 1964 inclusive.
Such a coin does not exist. The first Australian 2 cent coin was issued in 1966.