More than 320,000 Auckland households will get another $345 payout from lines company Vector.

The company's net profit rose 84 percent to $274.4 million, due to increased operating earnings, lower interest costs, favourable derivative movements and the $164 million gain on the sale of Vector Gas.

It has announced a slightly improved dividend for shareholders, up from 15.5 cents to 15.75 cents per share.

However, it has a higher number of beneficiaries this year in its area which covers Auckland, Manukau, northern Papakura and eastern Franklin.

The dividend is due late September or October.