April 22 (Reuters) - AMP Ltd said on Thursday assets under management at its Australian wealth management business increased by A$1.6 billion ($1.24 billion) in the first quarter on better market conditions and lower outflows from pension fund mandates. Assets under management at the unit jumped to A$125.7 billion in the three months ending March from A$124.1 billion at the end of December. ($1 = 1.2905 Australian dollars) (Reporting by Sameer Manekar in Bengaluru; Editing by Ramakrishnan M.)