Covered bonds are being put to work by banks for long-term funding after a period of inactivity.Offshore, National Australia Bank late last week sold €750 million of seven year covered bonds. With an order book of €1.0 billion, the indicative spread of 28 basis points over mid-swaps narrowed to 26 bps.The week before Westpac sold US$1.75 billion of five year covered bonds in the s144A market.However, Westpac New Zealand will commence a European roadshow today for a covered bond issue that will come from the first and only program to be registered with the Reserve Bank of New Zealand. New Zealand's covered bond legislation came into effect last December after being passed in parliament the month before.